I'll get a compression test done soon. In the meantime, do these symptoms ring any bells?

At idle, the car feels slightly funky - almost like a miss, but different. Driving slowly is the same - basically normal, but if you pay attention, something just feels "off". But when I get on the gas and start to build some boost (couple psi), the engine tone suddenly changes, and the car seems to stutter. It has little power at this point (though obviously I haven't pushed it - just 50% throttle till it starts happening).

This started happening suddenly while I was dialing in boost last weekend. I was on a WOT run, at about 20psi (car was tuned for 22psi, I'd been running 20psi most of the time, and no detonation). There was no knock event (I was logging at the time), AFRs were fine, but the car kinda bucked and lost power. Ever since, it's exhibited the behavior described above.

I replaced plugs (what a headache - only took 45 minutes to swap them, but NOBODY has plugs in stock. All the dealers would have had to special order them), since they were due to be replaced anyway. Exactly the same behavior after the plugs were replaced.

So, I'm ready for the worst, but what do you folks think? Oil seems fine (no coolant or strong gas smell). Coolant seems fine (it's green, not gassy or oily). No noticeable plumes of smoke from the exhaust.

You've checked for boost leaks?

You've checked for boost leaks?

Yeah. AFRs stay OK. Hoses and everything seem to be tight.

tried resetting the ECU?

tried resetting the ECU?

:) Yes. Had the battery disconnected while changing plugs. Same behavior afterwards.

Oil smells pretty gasoliney now. So I'm pretty sure it's not good news :p

A telltale sign of low compression is when you start the car..... when the car cranks it doesnt sound steady and uniform...... hard to explain on a computer but its definately a distnct sound at startup.

The easiest way I would describe it is "erratic cranking" if that makes sense to you.

A telltale sign of low compression is when you start the car..... when the car cranks it doesnt sound steady and uniform...... hard to explain on a computer but its definately a distnct sound at startup.

The easiest way I would describe it is "erratic cranking" if that makes sense to you.


I'd have to go start it again to double check, but that sounds pretty close.
It sounds kinda lopey or something. Even at idle just after starting, it sounds similar to a miss (as though a coil pack were disconnected), but different.

I'll have the compression gauge tomorrow and post results. I'm expecting at least a piston (ring/ring land), and just hoping it didn't score the cylinder wall...

try pulling the crank case vent hose while the car is running, if you get smoke, ya prolly blew a ring land

when you crank it, if you have a miss, it's a ring or land.

da-da-da-de-da-da

Jorge (RiftsWRX)
www.projectWRX.com

That sounds like what happened to my 02... it ended up being a clogged Cat. I ended up replacing my Downpipe and 3rd Cat to fix it.

That sounds like what happened to my 02... it ended up being a clogged Cat. I ended up replacing my Downpipe and 3rd Cat to fix it.


No cats here :)

And the verdict is?

Still haven't gotten my hands on a compression tester. Hopefully I can borrow a friends this morning and find out.

Bizarre. Just bought a compression tester and tested each cylinder. Basically 120psi across the board. The cylinder in the front on the driver's side was about 115psi. Passenger side back was 118psi. The other two were 120psi dead on.

What have others found the stock STi block to hold? I thought I remembered others saying around 120psi.

Now I'm just confused. It does sound kind of like an air leak that "blows open" at high pressure, but why would my air/fuel ratios stay "normal"? It should dive even richer if it's losing air...

Anyone have any ideas on what to check next?

Bizarre. Just bought a compression tester and tested each cylinder. Basically 120psi across the board. The cylinder in the front on the driver's side was about 115psi. Passenger side back was 118psi. The other two were 120psi dead on.

What have others found the stock STi block to hold? I thought I remembered others saying around 120psi.

Now I'm just confused. It does sound kind of like an air leak that "blows open" at high pressure, but why would my air/fuel ratios stay "normal"? It should dive even richer if it's losing air...

Anyone have any ideas on what to check next?

Do you have a boost guage in the car?

Do you have a boost guage in the car?

Yes, and a carputer on which I constantly log from my UTEC and Tuna.

Boost and AFR seems fine, which is why, although it almost sounds like an air leak, I'm skeptical. I don't, for example, get low boost, high MAF, and super-rich air/fuels...

:confused:

What confuses me is the normal AFR, based on O2 sensor readings, because it should pick up a clogged injector, bad injector, bad plug wire and bad coil pack, all of which can do this (and has done this on my old 2000 RST which acted like yours when it happened). YOU ALREADY VERIFIED THE PLUGS ARE FINE, which means no det, in agreement with your loggings.

If you had a boost leak after the MAF I'd expect a drop in boost and rich AFR. If you had a clogged fuel filter I'd expect lean AFR.

Compression is good, but what about a leakdown test? What about water in the gas?

What confuses me is the normal AFR, based on O2 sensor readings, because it should pick up a clogged injector, bad injector, bad plug wire and bad coil pack, all of which can do this (and has done this on my old 2000 RST which acted like yours when it happened). YOU ALREADY VERIFIED THE PLUGS ARE FINE, which means no det, in agreement with your loggings.

If you had a boost leak after the MAF I'd expect a drop in boost and rich AFR. If you had a clogged fuel filter I'd expect lean AFR.

Compression is good, but what about a leakdown test? What about water in the gas?

No leakdown test yet. Almost certain it's not the gas, because I was halfway through a tank when it happened. I mean, it is almost consistent with a hose that's blown off or maybe a bad injector that finally went south.

One other data point I just realized is missing from above. After a "stutter event", if I let it stutter for more than about .5 seconds, the CEL will flash indicating misfires (again, UTEC knock count stays at 0), but no code is stored and the CEL doesn't actually illuminate. So to clarify the timeline, it's give it ~50% throttle till it makes a couple psi, car will stutter while gas is held down, let off gas, and after about 3-4 seconds, CEL will flash a handful of times.

This apparent misfire is why I was convinced it was either plugs or a piston. When I took the new plugs out to do the compression test today, all 4 plugs showed the same condition, so I would have thought I could rule out plug wires, coil packs, etc. None was more or differently fouled than the others. (Same for the original plugs that I took out Friday - none was worse than any others. All just had the usual discoloration for a healthy used plug)

One more question for you ImprezaRS - how rich did your AFRs go with (I'm assuming) one non-firing cylinder?

Thanks for your help guys. I'm stumped.

More inconclusive info. I took the intercooler off to double check some more hoses and stuff. The throttle body makes a "whirring" noise that I don't remember hearing before (but it would have been much quieter with the intercooler on there). I checked the range and it still opens all the way and seems to be working fine. So I think this is nothing.

Also checked spark by putting a plug in each coil pack and verifying it was sparking - no problems with spark.

Now I'm wondering if I have an injector that's dieing. I'm running perrin modified stockers. Anyone know of a method to test them? I think I have access to my stock injectors (a buddy bought them but hasn't installed them), so I guess I could always swap back just to see if that's what's causing my problem.

More inconclusive info. I took the intercooler off to double check some more hoses and stuff. The throttle body makes a "whirring" noise that I don't remember hearing before (but it would have been much quieter with the intercooler on there). I checked the range and it still opens all the way and seems to be working fine. So I think this is nothing.

Also checked spark by putting a plug in each coil pack and verifying it was sparking - no problems with spark.

Now I'm wondering if I have an injector that's dieing. I'm running perrin modified stockers. Anyone know of a method to test them? I think I have access to my stock injectors (a buddy bought them but hasn't installed them), so I guess I could always swap back just to see if that's what's causing my problem.

The noise from the throttle is normal.

This might be something worth trying, replace the front O2 sensor(one on manifold). They have been known to go bad out of the blue and cause similar symptoms that you are seeing. Worth a try?

This might be something worth trying, replace the front O2 sensor(one on manifold). They have been known to go bad out of the blue and cause similar symptoms that you are seeing. Worth a try?


I guess it's possible that the sensor went south, but I really doubt it has anything to do with my problem. First, at idle, in closed loop fueling, AFRs stay right at 14.7, according to my wideband. And second, when the problem happens, it's at greater than 25% throttle, which means the UTEC is running fueling, in open-loop, without any regard for the O2 sensor.

Bump for the afternoon crowd? Any ideas? I'm kinda lost here - was convinced it was spark or piston...

i have stock injectors laying around...

...if you want to try them out, you can just send me money for shipping...and then if you end up needing them, you can send me the rest of the money, or else you can send them back?

No leakdown test yet. Almost certain it's not the gas, because I was halfway through a tank when it happened. I mean, it is almost consistent with a hose that's blown off or maybe a bad injector that finally went south.

One other data point I just realized is missing from above. After a "stutter event", if I let it stutter for more than about .5 seconds, the CEL will flash indicating misfires (again, UTEC knock count stays at 0), but no code is stored and the CEL doesn't actually illuminate. So to clarify the timeline, it's give it ~50% throttle till it makes a couple psi, car will stutter while gas is held down, let off gas, and after about 3-4 seconds, CEL will flash a handful of times.

This apparent misfire is why I was convinced it was either plugs or a piston. When I took the new plugs out to do the compression test today, all 4 plugs showed the same condition, so I would have thought I could rule out plug wires, coil packs, etc. None was more or differently fouled than the others. (Same for the original plugs that I took out Friday - none was worse than any others. All just had the usual discoloration for a healthy used plug)

One more question for you ImprezaRS - how rich did your AFRs go with (I'm assuming) one non-firing cylinder?

Thanks for your help guys. I'm stumped.

I used a Autometer AFR so it didn't give me numbers like 11:1 - it would switch from Stoich to rich at about 2 o'clock. It just went to past 3 o'clock on the rich, and my EGT would drop to below 1100 F. I leaned it out so much thinking it was a tuning problem that I cooked #4 cylinder. Turned out all the fuel from unburned #3 with the bad plug wire was being picked up by the EGT probe on #3 and the O2 sensor in the up-pipe that I leaned out #4 too much in my effort to fix it. Just shows why you should measure EGT on more than one cylinder, eh?

I have heard of a technique of measuring something like impedance or resistance on the plug wires to pick up a bad injector as well as picking up a bad plug wire - the values go in opposite directions if one or the other is bad. This is a device that clips over the plug wire and connects to the block, and I am not a mechanic to know what it is called.

I have heard of a technique of measuring something like impedance or resistance on the plug wires to pick up a bad injector as well as picking up a bad plug wire - the values go in opposite directions if one or the other is bad. This is a device that clips over the plug wire and connects to the block, and I am not a mechanic to know what it is called.

That works on the older cars with distributors, but aren't subies coil-on-plug?

Problem with the utec? Maybe take it out if the car will run semi right, or switch with a buddy.

The injectors are so large that it doesn't run well with the UTEC on the stock map mode.

Maybe I'll try it though.

I may see if I can get my hands on a subaru select or deltadash to get some more info. It's really strange. I put the intercooler back on - no signs of an air leak anywhere, but the problem is still there. Runs fine until I put some load on it, then boost goes up normally, MAF seems to match boost. The car is maybe a little richer than before, but I attribute this to the colder weather and the nature of the basemap.

It's the misfires that throw me off, though, and why does the CEL blink after I've let off? Does it always work on a delay?

The autometer afr gauge is not accurate. Anything below 13.4afr and it shows full rich.

Have you checked to see if it is a clogged fuel filter? There is some nasty gas out there these days with prices being so high. Seems you never know what you are buying, and gas stations trying to get every penny possible. just a thought.

Have you checked to see if it is a clogged fuel filter? There is some nasty gas out there these days with prices being so high. Seems you never know what you are buying, and gas stations trying to get every penny possible. just a thought.

I have not yet checked the fuel filter since it's a pita to get to.

Wouldn't a clogged filter show up as running lean though? My wideband O2 shows "normal" AFRs (if anything, slightly richer than a couple weeks ago when it was warmer).

The injectors are so large that it doesn't run well with the UTEC on the stock map mode.

Maybe I'll try it though.

I may see if I can get my hands on a subaru select or deltadash to get some more info. It's really strange. I put the intercooler back on - no signs of an air leak anywhere, but the problem is still there. Runs fine until I put some load on it, then boost goes up normally, MAF seems to match boost. The car is maybe a little richer than before, but I attribute this to the colder weather and the nature of the basemap.

It's the misfires that throw me off, though, and why does the CEL blink after I've let off? Does it always work on a delay?

Stop by and grab a new UTEC and our select monitor for a few quick runs on the road.

-Nathan
www.turboxs.com

it seems that most cars computer systems have a designated way of doing misfires.. Typically, the check engine light will flash when a misfire is detected, depending on duration of misfire, what percentage, etc. If it misfires more than 50% for more than "x" amount of time, then it will store a code in the system. Its strange, but its the way they do it, probably to not freak people out.

And believe me 50% feels like the cylinder is dead. If you have a good ear and access to a scanner that has capability for a misfire monitor, you can see just how bad it is, when it happens, etc. That can help determine what it could be.

For example, you could see which cylinder was misfiring, say, switch the coil pack to another cylinder, see if that one misfires.. If not, then its not a spark problem.. blah blah blah.

i'd say do a leakdown, just to be on the safe side.

It could be a coilpack going out. Only misfiring on load, etc. I've seen it on STi's before but at higher boost. <shrug> I'll talk to my Subaru Master Tech and see if he can think of anything either.
On a side note; you say "a little richer". How about some numbers?

Mark
www.Quantum-Racing.com
Home of the Dynapack Dyno

It could be a coilpack going out. Only misfiring on load, etc. I've seen it on STi's before but at higher boost. <shrug> I'll talk to my Subaru Master Tech and see if he can think of anything either.
On a side note; you say "a little richer". How about some numbers?

Mark
www.Quantum-Racing.com
Home of the Dynapack Dyno

Thanks to the awesome customer service of TurboXS (as always) and a little help from a friend, we confirmed it was a coil pack - number 1.

I wouldn't have expected a coil pack to die only under load, and would have expected to see some change in AFR.

As for numbers, at higher boost, it seemed to be running around 10.5 vs a tuned for number of 10.8. But, because of the misfires it was tough to see that consistently. It's also much colder (read: more air at a given boost) than it was when tuned.

Anyway, I swapped coil pack 1 with a friend, and it ran fine. Ordered a new pack - should be in tomorrow.

Thanks for your help guys!

So, since I searched and didn't find anything, I'll add some keywords here to maybe aid people in the future.

keywords: coil pack coilpack symptoms symptom stuttering bucking hesitation afr air/fuel spark plug sparkplug sparkplugs

how much was the coilpack? (just in case for future reference?)

interestingly enough...i had a lot of misfire issues when i went with the larger turbo setup. most of them came when the car was cold, affected cyls 1-4, but most of the time just cyl 2. then later on, i had more misfires that came when i would be doing WOT runs. mostly cyl 2, sometimes cyl 3. i swapped plus (1 step colder), but for at least 3-4 weeks after i replaced the plugs, the misfires were still consistently happening. heres the kicker- they eventually stopped. knock on wood, but i havent had a misfire for about a month now...i hadnt even modified my maps during the time they stopped. strange, eh?

glad you got things resolved though. now we can get back to testing out that new exh housing. :)

how much was the coilpack? (just in case for future reference?)

interestingly enough...i had a lot of misfire issues when i went with the larger turbo setup. most of them came when the car was cold, affected cyls 1-4, but most of the time just cyl 2. then later on, i had more misfires that came when i would be doing WOT runs. mostly cyl 2, sometimes cyl 3. i swapped plus (1 step colder), but for at least 3-4 weeks after i replaced the plugs, the misfires were still consistently happening. heres the kicker- they eventually stopped. knock on wood, but i havent had a misfire for about a month now...i hadnt even modified my maps during the time they stopped. strange, eh?

glad you got things resolved though. now we can get back to testing out that new exh housing. :)

Coilpack was $99.99 at the dealership.

I also had intermittent misfires in all cylinders, but only at low load. I would get a CEL every couple hundred miles, but then it would go away. Nathan suspected the Perrin injectors - another customer had the perrin modifieds, and they would fail to open occasionally at idle, because the on time was so low. Replacing the injector fixed it.

But I haven't had those misfires in a while - much like you, they just suddenly went away.

Back on 11/7 I suggested the coilpack and mentioned I'd had this same thing happen to me. Glad you got it figured out!

It could be a coilpack going out. Only misfiring on load, etc. I've seen it on STi's before but at higher boost. <shrug> I'll talk to my Subaru Master Tech and see if he can think of anything either.
On a side note; you say "a little richer". How about some numbers?

Mark
www.Quantum-Racing.com
Home of the Dynapack Dyno

That's what I was gonna say, but it looks like that was the problem.

I had a 2002 wrx that had the same exact problems. I was able to pull codes from the ecu, and the code pointed me to the exact "coilpack misfire".

Might want to get a obdii tool ;)

Back on 11/7 I suggested the coilpack and mentioned I'd had this same thing happen to me. Glad you got it figured out!

It was the first thing another friend suggested too. But a bench test showed that all coil packs were firing, so I wanted to do the compression test first, and wait for some help with a scanner to figure out where the problem was.

And I do need an OBD2 scan tool - it'll make it much easier to pinpoint the cylinder next time. :)

my misfire CEL came back on...cyl #2 again. i think ill just spring for a new coilpack this time and hope it doesnt happen again.

any ideas from TXS as to why UTEC equipped cars have failed coilpacks? i know everything is to spec in the hardware, but it may be too much of coincidence? i dunno.

when you guys call coilpack is it different than the coil over the plug? Or this is the same? I have a little idle problem(it "wonders" up and down) and a super high fuel consumption (about 210 miles per tank). I also once got a CEL P0103 ignition misfire cylinder 1 (but not again).

Cheers

Nick

The STi is coil-on-plug. That means there's no central coil pack with plug wires - the coil pack is a little brick with the plug connector right on it. It sits right in the spark plug well. It takes about 5-10 minutes to swap one out, depending on which one it is.

I've been getting an occasional CEL still as well. I suspect more misfires. I really need to get a scan tool ASAP to pinpoint where it is.

Are the coilpack failures specific to cars with UTECs? I figured it was just common to cars with higher than stock boost which stresses the packs.

ok got you thanks for clarifying. I already changed the plugs ans the old ones (old with about 7k miles) looked fine. I did a compression test as well and all cyclinders were dead on about 140. By the way I am not using a UTEC rather ECUTEC. I am also inclined to beleive that we are putting lots of stress on them.

Hey can you share the part number and where you got them?
If you do not want to in public shoot me a pm.

Regards

Nick

I don't recall the part number. I might be able to look it up when I get home. It was $99.99, and I got it from a local dealer. None of the dealers around here had them in stock, so I had to order it.

I don't recall the part number. I might be able to look it up when I get home. It was $99.99, and I got it from a local dealer. None of the dealers around here had them in stock, so I had to order it.


Got you. If you get a chance to locate that part number I would appreciate it very much. I went to Subaru parts.com but without the part number it makes it hard to find it.

cheers

Nick

I had a coilpack go bad, after I replaced it, idle and wot got much better, but the problem is still evident. I dont get any CEL's except when its raining sometimes. Has anyone traced idling issues to a coilpack without triggering a CEL. Also, I had my #3 go bad, and realized that everytime I spill coolant on the fill tank, it all runs down over the coilpack.

I had a coilpack go bad, after I replaced it, idle and wot got much better, but the problem is still evident. I dont get any CEL's except when its raining sometimes. Has anyone traced idling issues to a coilpack without triggering a CEL. Also, I had my #3 go bad, and realized that everytime I spill coolant on the fill tank, it all runs down over the coilpack.


what do you mean when you say the idle got better but the problem is still evident? And what are the CEL's when it is raining. I only got my CEL once and never again. It is obvious that the car misses at WOT. I have been running the car for like 2-3 weeks. By the way I use ECUTEC as my EM.
The thing that baffles me is the fuel consumption. I need to have a wideband and possibly a few dyno runs that would record the AFR.

Cheers

Nick

I also have intermittent idle issues - as I come to a stop with the clutch in, it will idle at around 1500-2000rpm, and slowly come down. Oddly, if I let off the clutch, it tends to drop to normal quicker, very consistently. No idea if this is related.

I'm still getting intermittent CELs, but don't yet have a scanner to see what they are. These CELs light occasionally when I floor it, but they go away after just a few drive cycles (last time, the misfire CELs would stay on for probably 30-40 cycles, so I don't know what these ne CELs are).

I believe I need to lean the car out a bit, since I've fiddled with a couple things since the tune. It's running low 10s now at medium-high boost, which may be safe, but I think is leading to misfires.

Anyway, I dropped off the coilpack at TXS today to take a look and noticed the part number is on the box. Oddly, it's got two different numbers.

The shorthand name is COIL ASSY-IGN. One one sticker, it has a part number of 22433AA540, but on another sticker, the number is 22433AA480. I don't know why there is this discrepancy. As far as I could tell, there was no Subaru part number stamped directly on the pack (there were other numbers, but I don't think they'd be useful).

I have some used coil packs off an o2 rex in case any of you guys would like to save some money. I will sell them for $45 each shipped...to the lower 48.

And I had no misfire problems etc. before motor was stripped.

PM or e-mail if interested.

well actually it seems that both the part numbers points to the same entry in the subaruparts.com search. They show them for like $76.xx.

http://www.subaruparts.com/cart/?pn=22433AA580


cheers

nick

well I am not sure that the coilpacks of the WRX and STi are the same can anyone verify?

Cheers

Nick

I'm almost positive the coil packs are not compatible between EJ205 and EJ257

I'm almost positive the coil packs are not compatible between EJ205 and EJ257

this is my suspicion as well. I have heard that they are even different color.

But we still need to verify. they must have a different part number?

cheers

Nick

The 540 code says that can't find anything that matches. If I had to pick a part number anyway based on the stickers, it'd be the 480 number. That one is on a more "official" Subaru sticker. The other part number is on a sticker that includes my name, like it was part of a shipping order kind of thing.

They're definitely a different part number. Part num is 22433AA421 for the EJ205 engine.

But they are similar, so it's possible they are electrically compatible. I've heard that the WRX has a plastic plate where the STi is a metal plate in the bracket that holds the pack in the spark plug well. The STi is definitely metal, but I've never held a WRX one to notice.

interesting try this:

http://www.subaruparts.com/cart/?pn=22433AA480

the link for the WRx one it shows the same price but different part.

http://www.subaruparts.com/cart/?pn=22433AA421+&submit.x=17&submit.y=2

I just ordered one total with shipping about $85.


Nick

Well, I was having idling problems, replaced/swapped/troubleshot every sensor in the engine bay, check for vaccum leaks, pressure check intake system. Then I had a coilpack noticably go bad, once boost hit the car would stumble like a major boost leak. I replaced the bad coilpack, car runs like before. What I'm getting at: maybe idle only is effected by a minor coilpack defect. I know people who have had severe idle problems but perfect WOT w/ bad coilpacks. Then in my case, severe WOT throttle problems. So maybe I have another coilpack that is going bad that is only effecting idle. Oh yeah, if i sit at a light for more than 20secs, my idling will start dancing around, but afr is steady and timing jumps around a tad more than normal.

what do you mean when you say the idle got better but the problem is still evident? And what are the CEL's when it is raining. I only got my CEL once and never again. It is obvious that the car misses at WOT. I have been running the car for like 2-3 weeks. By the way I use ECUTEC as my EM.
The thing that baffles me is the fuel consumption. I need to have a wideband and possibly a few dyno runs that would record the AFR.

Cheers

Nick

interesting. I am not sure but have you had your ECU reflashed or something? Or is it stock. Mine is reflashed/scled for PE850's. Mine at WOT it misfires and at idle it wonders between 740-850 or so. It does not do it when the car is cold and the idle is higher than normal. It only does it when the car is well warmed up and I am idling as well as at WOT (high load). I am guessing since I got the CEL once for cylinder #1 this is the bad coilpack. As I said I will replace it and see if that fixes the problem.

Cheers

Nick

When you say it misfires, are you getting the flashing CEL, or is it bad enough for the computer to record but not enough to flash (or illuminate) the CEL?

Just curious because previously, before the coil pack totally died, I would get flashing cells for misfires every once in a while. Now with the coil pack replaced, I have other strange behavior, including occasionally an illuminated CEL that goes away after just a few drive cycles, but no more flashing CEL. I suspect more misfires, but I don't know if there is a level of misfiring that's enough for the computer to note, and eventually illuminate the CEL, but not enough to flash it during the event.

(Did that make any sense?)

well I only got a P0301 C1MD once. I have been driving the car for like 2 weeks and no CEL. But when I get on it I can feel it cutting out. Like it runs on 3 cylinders. I am guessing that the coil cuts out when there is a load and the fuel gets dumped. When I feel it and let the gas (or back off) gas gets burned and the plug cleans up. this is why I did not see anything on the sparkplug. And again the idle wanders up and down between 740 and like 850 rpm.

Cheers

Nick

well I only got a P0301 C1MD once. I have been driving the car for like 2 weeks and no CEL. But when I get on it I can feel it cutting out. Like it runs on 3 cylinders. I am guessing that the coil cuts out when there is a load and the fuel gets dumped. When I feel it and let the gas (or back off) gas gets burned and the plug cleans up. this is why I did not see anything on the sparkplug. And again the idle wanders up and down between 740 and like 850 rpm.

Cheers

Nick

Ok, that sounds exactly like what I was experiencing. I thought yours was more "subtle" :)

My money's on the coil pack.

This is my idea as well. I will update when I receive it and install the new coilpack.

cheers

Nick

ok I got the coilpack today.

Now the dumb question of the day which cylinder is cylinder number one?

I thought it was the one on the passenger side to the front of the car?

front
of
the car
21
43
rear of the car

Cheers

Nick

ok I got the coilover today.

Now the dumb question of the day which cylinder is cylinder number one?

I thought it was the one on the passenger side to the front of the car?

front
of
the car
21
43
rear of the car

Cheers

Nick

You got it right.

Cyl 1 was the bad one in my car too. I hope you have a short ram intake - it makes number 1 the easiest to change :)

lol ok I just finished. and no I have the stock intake. Oh so easy to access the plugs on our nice subies :)

put it back together but I have no will to go out driving it at 10:30pm. I have to drive to work in traffic so that will be the test first thing tomorrow morning.

Cheers

Nick

well idle is still wobly. I was in stop and go traffic so I obviously did not press it so I could not tell if it is misfring under load. I will sit on it for a day or two. I changed the cylinder one coil pack because one time it threw a misfire code. But it never did it again so it may not be that coil pack . Next solution is to switch coils around until I hear a difference. I am not ready to go buy 3 more coil packs. We will see.

Cheers

Nick

Sorry for bringing this thread back up from the dead. The symptoms described by the OP match what I am experiencing. What does it sound like when one coilpack is bad when accelerating under load and in boost? Is it like a muffled put-put-put sound from the engine bay?

That is exactly how my 06, wrx sounded under boost with a bad coil pack.a bad coil pack is hard to find; go up a long easy grade[2-3%]in 3rd or 4th and slowly bring on boost; it will feel like a hesitation, sputtering, etc., at the same boost each time.