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Old 01-02-2007, 06:55 PM   #1
lewisd
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Question Jerky throttle with 2006?

Does anyone else have the problem where, when you let off the throttle at some RPMs at certain speeds (a fairly wide range), you'll get a bit of a jerk, no matter how smoothly you let off? I posted (can't find it) when I first got the car and noticed it, and some people had the same problem, so it wasn't just me. Is there a fix for this yet?
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Old 01-03-2007, 11:52 PM   #2
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manual or auto and in what gear? ya gotta give us a little help if we didnt read the first one.
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Old 01-04-2007, 12:29 PM   #3
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Originally Posted by snowman87 View Post
manual or auto and in what gear? ya gotta give us a little help if we didnt read the first one.
Right, sorry. I was just really hoping this was a widely known issue by now.
I have a manual, I don't know if this happens on the auto.
It happens in any gear, but it's more noticable in the lower gears.
The most common place I notice it is when driving down a very slight incline. Say I'm in 3rd, and I have my foot just barely on the gas, and I notice that because of the incline, I'm speeding up slightly thanks to the combination of gravity, and my foot on the gas. When I slowly try to move my foot to give less gas, as I come off the pedal, there's a bit of a jerk, and I start slowing down faster than I wanted. So then I have to give it just a tiny bit of gas to maintain the right speed, and as I put my foot back on the gas, there's a jerk again, and I start accelerating, instead of maintaining speed.
It's like the difference between "no throttle" and "minimum throttle" is too large.
I can experience the same thing driving around a parking lot in 1st.
I'm pretty sure this whole thing is as a result of the new-to-2006 drive-by-wire throttle setup, but I'm really hoping there's an ECU flash out there that will fix it.
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Old 01-04-2007, 03:41 PM   #4
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Default I Have the same issue

I just purchased a 2006 Saab 9-2X 2.5i (Impreza Wagon) and I noticed the same thing. Lift off the gas even a small amount and I get a jerk just as you described. It must be the drive by wire. I will watch for answers in this and other forums because it can drive me crazy. Just wanted to confirm it is not just you.
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Old 01-04-2007, 03:49 PM   #5
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I have the same problem in my 2.5i in 3rd gear also. Happens in first when im slowly going in a parking lot...dont really notice it in second. 3rd gear is when it is most noticeable for me. I would say its normal. I was also told that the 2-3 shift is the most abrupt on imprezas as they are loud and harsh cars.
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Old 01-04-2007, 03:53 PM   #6
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Quote:
Originally Posted by soobiesvx93 View Post
I have the same problem in my 2.5i in 3rd gear also. Happens in first when im slowly going in a parking lot...dont really notice it in second. 3rd gear is when it is most noticeable for me. I would say its normal. I was also told that the 2-3 shift is the most abrupt on imprezas as they are loud and harsh cars.
Ok, glad I'm not the only one. I still want a fix though.

As for your second comment... my problem doesn't have anything to do with actually shifting, so I'm not sure how the 2-3 shift being "abrupt" is related. Anyways, in a manual, a shift shouldn't be abrupt unless you're shifting that way. *shrugs* I can change between any gears in the car smoothly, just fine.
What I can't do is just drive smoothly, because I inevitably run into this stupid jerky throttle.
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Old 01-04-2007, 04:01 PM   #7
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Originally Posted by lewisd View Post
Ok, glad I'm not the only one. I still want a fix though.

As for your second comment... my problem doesn't have anything to do with actually shifting, so I'm not sure how the 2-3 shift being "abrupt" is related. Anyways, in a manual, a shift shouldn't be abrupt unless you're shifting that way. *shrugs* I can change between any gears in the car smoothly, just fine.
What I can't do is just drive smoothly, because I inevitably run into this stupid jerky throttle.
Oh i was just mentioning the part about the shift . It didn't have to do with your post. But I have the same issue as you do so I think its a normal thing. Its my first manual car so thats why i was a little concerned too.
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Old 01-04-2007, 06:21 PM   #8
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yea i do have that problem ive just learned to adapt my driving to avoid it, i dont really notice it much anymore you just have to know its going to happen and leave space to accomidate for it.
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Old 01-11-2007, 12:09 AM   #9
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It maybe drive-by-wire, but it could also be, the factory computer, tune-wise. I have seen severely lean air fuel ratios, at low rpm/high load, w/ the newest Subaru's. Perhaps, it's the design/way that our dyno load's Subaru's, but the 05's seem to be pretty good, for being in closed-loop. But the 06+, really seem to run lean, anything before 3800-4000 rpms.
I have had very strang things happen w/ drive-by-wire cars, especially Subaru's, on the dyno.
A lot of the time, you can make a pull, sometimes the cars are jerky w/, rpm's less-than 3000 rpm and under loaded rollers, switching gears. But the worst, is severe idle-up on decel, when coming down from 120+ mph. The revs start increasing rapidly. S0, in the past, I have lessend the dyno brake, and it would still continue to climb. I have had to shut the cars down, before the rollers are stopped. I have seen it in, Acura/Honda, AUdi, VW, Subaru, and Toyota. Mitsu seems to be ok.

I do understand the drivability difference between mechanical and electrical. I prefer a linkage. I can always tune in, tip-in throttle changes to help such things. But w/ a factory computer so complex and w/ DBW installed... you have your options of tuning electronics, or the ability to learn how to drive, drive-by-wire. Your factory computer interputes what you are doing w/ the pedal, but is does not react instantly...

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Old 04-30-2008, 10:00 PM   #10
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time to resurrect this topic. I have been having this problem for a long time at service they never could find anything. I was wondering if anyone has any updates on this
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Old 05-13-2008, 06:29 PM   #11
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yeah i was noticing the other day ... i was in 3rd at like 1500 rpms in traffic and everytime i pulled my foot off the gas ... she started bucking like a bronco! i sometimes feel like a complete A$$ cuz i know people look at my car bucking and go "damn ... this kid needs to learn how to drive stick!" lol. but yeah idk ... i hear it's a common problem and it is most likely because of the DBW throttle set up. I believe i heard that Throttle body spacers cut's down on that a little (not 100%) and also a grounding kit i've heard has helped as well. I found those things on the forums. idk ... i've learned to just push the clutch in right be4 that bucking point and just roll.
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Old 05-13-2008, 06:47 PM   #12
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i really think it's the drive by wire or some electric juju...because after i installed a grounding kit, my wife noticed that there was much less jerking around the parking lot, etc. i said whatever...cause i didn't believe it but after many other comments, i do think it made a difference.

i wanted something nice but not expensive so i picked up a kit from ebay. it was cheaper than the top of the line kit sold by pf so i went for it...it was by flex innovations...great kit...i still can't believe i bought from them cause they had ZERO feedback when i purchased it...I COULD'VE GOTTEN SCREWED! but i didn't!!!

T
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Old 05-14-2008, 02:45 AM   #13
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Hey found the pic on ebay, is this it?

http://cgi.ebay.com/ebaymotors/ws/eB...m=320252131094

engine bay pic looks clean. Thats the kind of install i would go for the OEM look.

Quote:
Originally Posted by Tahoe SC View Post
i really think it's the drive by wire or some electric juju...because after i installed a grounding kit, my wife noticed that there was much less jerking around the parking lot, etc. i said whatever...cause i didn't believe it but after many other comments, i do think it made a difference.

i wanted something nice but not expensive so i picked up a kit from ebay. it was cheaper than the top of the line kit sold by pf so i went for it...it was by flex innovations...great kit...i still can't believe i bought from them cause they had ZERO feedback when i purchased it...I COULD'VE GOTTEN SCREWED! but i didn't!!!

T
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Old 05-22-2008, 09:54 PM   #14
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i have the same jerking problem in my 07 2.5i. it drives me nuts as its my first drive-by-wire manual and my first AWD. i've also been driving my car for a year now and still can't get adapt to the clutch. its the combo of enough throttle to engage the all-wheel drive and actually getting the drive-by-wire to respond quickly enough otherwise the car bogs out. i'm no rookie to a manual tranny either but i just can't find the happy medium. it literally drives me crazy.
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Old 05-23-2008, 02:06 AM   #15
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Originally Posted by Shiz36 View Post
i have the same jerking problem in my 07 2.5i. it drives me nuts as its my first drive-by-wire manual and my first AWD. i've also been driving my car for a year now and still can't get adapt to the clutch. its the combo of enough throttle to engage the all-wheel drive and actually getting the drive-by-wire to respond quickly enough otherwise the car bogs out. i'm no rookie to a manual tranny either but i just can't find the happy medium. it literally drives me crazy.
I know exactly where you're coming from and it's very frustrating. The problem is usually at low speeds in 1st and 2nd gear usually crusing at the parking lot or stop and go traffic. It's so bad it gives me a headache sometimes. It's also embarrasing to have that happen to you with passengers in the car because the jerkiness reflects poorly on the manual driver and on the car.

It is true that the drive-by-wire (DBW) throttle systems have something to do with the bucking. DBW relies on the soundness of the car's electrical system to send messages back and forth from the pedal to the ecu to the engine. What i've found out from research is that the abrupt accel/deceleration is due to poorly grounded electrical system in the wrx.

And so I researched what grounding kits are out there, and found a few that were overly priced from big name companies. So I turned to ebay and found the best quality kit for the money from a new company called Flex Innovations.

They were selling kits that were custom fitted to 06-07 wrx so I tried it out and was surprised to actually notice a difference in the way the car behaved. First off, acceleration was noticeably smoother and the jerkiness was reduced quite a bit. It subsided enough that it just happened in background and I didn't notice it anymore. Problem solved!

Check this out:
http://cgi.ebay.com/ebaymotors/ws/eB...m=320255409482

It worked for me maybe it can work for you.
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Old 05-23-2008, 02:50 PM   #16
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Quote:
Originally Posted by efaroh View Post

Check this out:
http://cgi.ebay.com/ebaymotors/ws/eB...m=320255409482

It worked for me maybe it can work for you.
Thanks for the link. I just asked this seller if the kit will fit a 2.5i, I assume it will but I want to hear it from him. If so I'm gonna grab one and I'll report the results on my 06 2.5i.

---for $45.00 shipped, its worth a shot, that whacky throttle has been bugging me for almost two years now.
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Old 05-27-2008, 03:08 AM   #17
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Seller would not guarantee the kit would fit, only for the WRX specifically. Anyone know if it would fit a 2.5i?
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Old 05-27-2008, 10:02 PM   #18
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Quote:
Originally Posted by efaroh View Post
I know exactly where you're coming from and it's very frustrating. The problem is usually at low speeds in 1st and 2nd gear usually crusing at the parking lot or stop and go traffic. It's so bad it gives me a headache sometimes. It's also embarrasing to have that happen to you with passengers in the car because the jerkiness reflects poorly on the manual driver and on the car.

It is true that the drive-by-wire (DBW) throttle systems have something to do with the bucking. DBW relies on the soundness of the car's electrical system to send messages back and forth from the pedal to the ecu to the engine. What i've found out from research is that the abrupt accel/deceleration is due to poorly grounded electrical system in the wrx.

And so I researched what grounding kits are out there, and found a few that were overly priced from big name companies. So I turned to ebay and found the best quality kit for the money from a new company called Flex Innovations.

They were selling kits that were custom fitted to 06-07 wrx so I tried it out and was surprised to actually notice a difference in the way the car behaved. First off, acceleration was noticeably smoother and the jerkiness was reduced quite a bit. It subsided enough that it just happened in background and I didn't notice it anymore. Problem solved!

Check this out:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMESELX%3A IT&viewitem=&item=320255409482

It worked for me maybe it can work for you.
Thanks for the tip. How hard was it to install?

Quote:
Originally Posted by moestock View Post
Seller would not guarantee the kit would fit, only for the WRX specifically. Anyone know if it would fit a 2.5i?
I'm curious too if it fits the 2.5i. I just wish SOA would release a service bulletin or something for a ecu fix.

Maybe efaroh can post a close up of his engine bay with the wires to compare against the 2.5i as far as mounting locations. See if there's any difference...
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Old 05-28-2008, 02:05 PM   #19
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i have the WRX kit, i don't think it will fit the 2.5 though. i've compared the pix and the 2.5 intake area is much different. PF has some install pix on the 2.5 rs forum. if you can get an idea of where they are and take the measurements, then the flex guy can make them, at least this is what he told me when i inquired about kits for my wife's murano.

PF's kit will fit but for sure, but for the price, i'd go with the flex kit cause the finish is much better.

the install was super easy, like 15 minutes.
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Old 05-28-2008, 02:10 PM   #20
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i will post side by side pics of engine bay once i get a chance. i'm at work so gimme a sec.
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Old 05-29-2008, 01:48 PM   #21
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IMHO, I don't think it's the DBW.

I have an 06 manual wrx and it does the same think under specific conditions.

The reason for this, is the REAR DIFFERENTIAL MOUNT BUSHINGS. What's happening is when you are on throttle, even slightly, the drive train is loading the engine. When you let off the gas, then this changes to the engine loading the drive train. This reversal in forces causes rear differential with relatively compliant bushings to go from one wound up state to the other in a sudden change. This, incidentally is the same acceleration clunk you feel particularly when going from 1st to 2nd.

If you want to reduce this bucking, you can adjust your driving style and/or get the TIC rear diff bushing inserts.

Personally, I'm choosing to keep the bushing because it saves some wear n tear on the drive train when I make a shifting mistake. Plus, it really doesn't play much of a role when you're actually on the track. It's more annoying on the street.

To avoid this, you can't just "work the the throttle slowly". You need to think of it as a loading system. When accelerating and you know you need to let off the gas, you need to smoothly reduce throttle and allow the momentum of the car catch up to power you're asking the engine to deliver... ie reach an equilibrium. When this happens, the bushing relaxes (nearly) back to resting state and you have "unwound" the bushing. Now touch the brake with the intent of winding up the bushing "the other way"; after winding, then apply the brakes to slow the car.

Disclaimer: it's actually not this simple, and there are way more components in the system that contribute to the bucking behavior as a whole, but I think the rear diff bushings are the most significant weak link.
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Old 05-29-2008, 02:47 PM   #22
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ive got the same issue. glad someone revived this thread as i never saw it the first time it was created. glad im not the only one experiencing this. its definitely a pain i 1st and 2nd gear when the car start jerking just because my foot isnt on the gas.

chimchimm5, if the issue is the bushings, based on how jerky the car can be, wouldn't we still hear the clunk from the real diff just as we do when shifting is off between 1st to 2nd as you described since it would be the same effect just in deceleration rather than acceleration?
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Old 05-29-2008, 03:00 PM   #23
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Quote:
Originally Posted by roccer View Post
ive got the same issue. glad someone revived this thread as i never saw it the first time it was created. glad im not the only one experiencing this. its definitely a pain i 1st and 2nd gear when the car start jerking just because my foot isnt on the gas.

chimchimm5, if the issue is the bushings, based on how jerky the car can be, wouldn't we still hear the clunk from the real diff just as we do when shifting is off between 1st to 2nd as you described since it would be the same effect just in deceleration rather than acceleration?
But you don't always have to hear/feel the clunk to experience the wingup/down of the bushing. I think the clunk is an indicator that you are REALLY slapping the drive train. But the cause of the clunk is still there at lesser applications. I'm guessing the bucking comes from the loads bouncing back and forth in the system and exacerbated by the rear diff bushing. If we had a camera looking at the bushing during the bucking, we'd see it whipping back and forth with every buck.

The wind up delays the transition and then it's like it slings the load. Much like making a sudden sharp turn with a soft suspension... slow initial transition and then a whipping.

That's my guess. And thinking about it this way has allowed me to adjust driving inputs to avoid bucking completely... unless I goof up or am not paying attention.
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Old 05-30-2008, 01:35 AM   #24
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Suddenly my extended warranty doesn't look like a waste of money anymore
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Old 05-30-2008, 10:01 AM   #25
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Suddenly my extended warranty doesn't look like a waste of money anymore
doesnt seem to do any damage (that i can tell) to the car (or any severe damage). its just damn annoying.
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