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Old 03-01-2008, 12:13 AM   #1
MYfirst00
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Satin White Pearl

Default Problem: Bogging, Low Idle, Idle Popping

So I bought a used 2000 Legacy GT with the 2.5L SOHC two weeks ago. When I test drove it, it would stall out at every stop when driving. A Subaru dealer who regularly serviced the car (person who owned it worked at a Subie dealership) reflashed the ECU and replaced the front O2 sensor, and had also recently cleaned the IAC valve. The stalling stopped and everything was normal.

Problem Part 1 - 2/27/08
I noticed in recent days the car would kinda stumble a little at idle but the RPMs would stay at a flat 700rpm. Yesterday on the way home in a snow storm, the car did not want to drop revs below 2500rpm when shifting. When I pushed in the clutch, the revs would actually raise 500rpm to about 3000rpm. When releasing the clutch and getting the rpms to drop below 2500, they would drop down to 700rpm then raise to a steady 1000rpm. When stopped and fully warmed up the next day, the rpms would still stay at a steady 1000rpm.

Under 3/4 or more throttle, the engine would also buck and then come back to life after a second or two.

There are no CELs at all which is the weird part.

Problem Part 2 - 2/29/08
Well I just replaced the rear O2 sensor and reset the ECU. Didn't change a thing with full throttle bogging. Instead of the car not dropping RPMs, it drops to 500rpm and wants to die out. It actually stalled once as i pulled into my driveway after the test drive. I'm also hearing some exhaust popping at idle. I ran it on the highway and under full throttle managed to get the CEL to flash 8 times at two different points, but it didn't record a CEL code. I searched an it looks like it might be a misfire problem. I think my next step will have to be try replacing the plugs and wires and see if that changes anything. I really don't want to bring it to the dealer to scan everything.
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Old 03-01-2008, 09:34 AM   #2
flstffxe
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I would check for a vacume leak, depending on where they are at, they can mess with the idle a lot. Check all the hoses, maybe even the gasket around the IACV. A vacume leak would be my 1st check then move on from there to ignition(plugs,wires...) and fuel(fuel filter, plugged/stuck injector/s....)
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Old 03-01-2008, 09:35 AM   #3
Subie Gal
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well....


you can keep guessing at the problem

or you can get it to a subaru dealer and a subaru scan tool

at least pay to have them diagnose it properly

then you will know what parts you need to buy

misfires can be really tricky.....

Jamie
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Old 03-01-2008, 11:10 AM   #4
flstffxe
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^^ no offense but not every one has the pocket books for the dealer or even a private shop for that matter. Before the days of cars having a computer you had no choice but to narrow down the options, may be old fashion but it still works. Hell it's how many people start out on their way to becoming a great mechanic, maybe even one at a dealer . If you can afford it I am all about paying some one else to do work.
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Old 03-01-2008, 12:20 PM   #5
MYfirst00
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True but sometimes the dealer has the equipment to fully diagnose the problem, and if they have good mechanics with history in Subarus then I'd rather have them chase non-CEL issues. I have an appt at 1:30 with North End Subaru. Hopefully they can figure it out. If I had time I'd swap out the plugs and wires, but every time I've had plug issues its thrown a misfire CEL. This is the first time I've experienced a blinking CEL in any of my 10 Subarus.
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Old 03-01-2008, 02:57 PM   #6
Subie Gal
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Quote:
Originally Posted by flstffxe View Post
^^ no offense but not every one has the pocket books for the dealer or even a private shop for that matter. Before the days of cars having a computer you had no choice but to narrow down the options, may be old fashion but it still works. Hell it's how many people start out on their way to becoming a great mechanic, maybe even one at a dealer . If you can afford it I am all about paying some one else to do work.
yeah so... let's toss $100 02 sensors at it

then $40 in plugs

then $$$$$....


no offense....

but it's good sense and probably financially smart to find out what's wrong
when it's not obvious.... (as in this case)

for a $50-90 diagnostic fee, at least you will know exactly what is needed,
and may save yourself loads of $ and frustration in the long run

rather than spending $200-$300 or more .... guessing
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Old 03-01-2008, 04:27 PM   #7
MYfirst00
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actually if I did the cheap route I could have stopped after part two, Jaime

I just got back from a visit to the dealer. My fav mechanic was there, heard my whole story and went to work. An hour later he came back and brought me over to the car. He showed me how the ceramic part of plug #2 had a crack down the entire side of it with carbon outlining it. He also showed me that the 135k mile plug wire for #2 was seperated inside the boot. The metal had seperated itself from the wire inside the insulation. So #2 was pretty much arcing to the engine. $160 later for plug/wires and labor, plus $109 O2, car runs like mint.

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Old 03-01-2008, 04:27 PM   #8
Subyroo2.5
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Quote:
Originally Posted by Subie Gal View Post
yeah so... let's toss $100 02 sensors at it

then $40 in plugs

then $$$$$....


no offense....

but it's good sense and probably financially smart to find out what's wrong
when it's not obvious.... (as in this case)

for a $50-90 diagnostic fee, at least you will know exactly what is needed,
and may save yourself loads of $ and frustration in the long run

rather than spending $200-$300 or more .... guessing
I know there is so many people out there that just throw parts at a problem and before you know it you have that much in it and no idea what the problem is!!
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Old 03-01-2008, 04:30 PM   #9
flstffxe
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I was not intending to knock dealers or other shops down. I was implying that every mechanic has to start some where. I have taken vehicles to a dealer/shop to have them fix it if I had the funds and it was -xx degrees out side, I am not anti dealer/shops like many of the people on here, nor will I slander a shop.

As I said
Quote:
Originally Posted by flstffxe View Post
If you can afford it I am all about paying some one else to do work.

My only catch is when a problem is pre diagnosed and you tell them what it is. Then they try to pull the "well we have to run a diagnostic which is $XX.xx - XXX.xx". Sorry I am not paying you to tell me what I already know and have informed you of. If I want you to replace______ and it doesn't fix the issue, well thats on me. Like I say, that is my only catch, I don't even mind the labor rates(they have electricity, gas, water, insurance, wages and more to pay). Most of the time the techs/mechanics only get ~15-30% of the hourly labor rate, the majority of the rest is overhead and the remaining small percentage is left profit. You agree?


Quote:
rather than spending $200-$300 or more .... guessing
I am not one who favors throwing parts(guessing) at car in hopes of getting lucky (I have seen shops do this too). I prefer a process of elimination, the same thing good shops do. Not every thing can be diagnosed with a scan tool either, like some vacume leaks, head gaskets issues...you get the idea. some times like myfirst00 said it comes down to "good mechanics with a history"

In short shops are good if you:
A. can afford one
B. don't feel comfortable with your skill level/knowledge
C. don't have the time/resources

Subie Gal/Myfirst00 I didn't mean to come off anti shop/dealer. sorry if I did.
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Old 03-01-2008, 04:40 PM   #10
MYfirst00
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^ Oh no worries. Everyone uses dealers for different reasons. I like mine because if i tell them to do something, they do it. my mech usually sets up the work order so i get the best possible price and usually doesn't charge me for figuring out the prob.
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Old 03-01-2008, 05:00 PM   #11
flstffxe
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^^ Thats how a service center should be, it keeps customers coming back.

edit: I just seen you got it solved in post 7. Glad to see it is done.
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Old 03-03-2008, 12:59 PM   #12
MYfirst00
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Well, it turns out I had a combination of problems. The day after I got the plugs and wires swapped out, the non-dropping rev and 1k idle returned. Car drove fine other than when when you took the air away from it. So I got out the tools and took off the IAC (damn rubber gasket ripped too). It was pretty dirty on the return into the engine and decent inside the valve itself. I got out the B-12 Chemtool and douched the hell out of the IAC valve and throttle body holes till they looked new. Started the car up and burnt out the carb cleaner, and took it for a spin. Ran mint. Revs dropped very quickly, slowed descent at 1k (normal) and rested at 700 on the money. Started up and idled normal this morning. It acted up a little bit on the commute to work but when I got to work it idled fine. It's definitely the IAC valve that's causing the idle air issue. It looks like the sensor is spring loaded in the IAC valve so maybe those wear down over time. I may get either a new or a used IAC to test the theory but all in all it's not too bad after the cleaning. I'd rather have some backups though!
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Old 03-16-2008, 01:14 AM   #13
sean ocallaghan
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i have a 2000 wrx with new rebuilt motor. idle was sort of playing up before now all the time where it pops constantly and also revs drop to about 200 rpm when putting foot on clutch then it lifts up tried changing IAC didnt make difference please someone help. very frustrated
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Old 03-17-2008, 07:26 AM   #14
MYfirst00
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Sean,
You'll probably want to post that in the Forced Induction forums since the turbo motor is a bit of a different beast than the N/A.

Ryan
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Old 03-17-2008, 10:04 AM   #15
sailil
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(Especially since there were no WRXs in the US until 2002. Non-US WRXs may well have a lot different from USDM engines anyway.)
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