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Old 05-30-2008, 12:49 PM   #26
efaroh
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Okay i didn't get around to taking pics of my engine bay, but I found a picture of flex grounding kit in wrx engine bay. comparing the pics, it looks like the throttle body is different.

Flex Grounding Kit on 06-07 WRX


Engine bay 06-07 2.5i
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Last edited by efaroh; 05-30-2008 at 12:59 PM.
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Old 06-25-2008, 02:56 AM   #27
mellow
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I just bought an 06' 2.5i wagon on sunday, and mine is doing this same thing in mostly 3rd gear and 1st at around 1500-2000 RPMS.

Last edited by mellow; 06-25-2008 at 03:21 AM.
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Old 06-25-2008, 04:53 AM   #28
chimchimm5
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Quote:
Originally Posted by mellow View Post
I just bought an 06' 2.5i wagon on sunday, and mine is doing this same thing in mostly 3rd gear and 1st at around 1500-2000 RPMS.
rear diff bushing wind up

In addition to the slow smooth let off, pause for a moment when you're changing from stepping down on the gas to letting up. This lets the bushing unwind.
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Old 10-21-2010, 10:37 PM   #29
SC_TBFD
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Quote:
Originally Posted by lewisd View Post
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.
Digging up an ancient thread.... again....

This is the best description of this problem. It's changing from 'coasting' in 2nd or 3rd to 'ever so slightly, as little as you possibly can, just barely touching' the accelerator at low(below 2500/2000) rpm. Following a another car in the city down a slight incline is exactly the situation it happens in. I think the initial jerk of acceleration pulls your foot off the throttle which makes the situation worse. Is there any new info on this, I feel like it's getting worse in my '06 2.5i
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Old 10-30-2010, 01:41 PM   #30
Tanuki505
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My wife hates riding in my WRX 06 and is alway yelling about it being jerky no matter how much I try to drive nice.... It's just the car.
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Old 10-30-2010, 09:49 PM   #31
hillsboro
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This is normal for a wrx or sti from what I've seen. I put 90,000 miles on my 02 wrx and it did the bucking thing. I tried switching from an aftermarket bov back to the factory. Didn't make any difference. I have had 2 sti's since and they all do it. This is a good thread though, it freaked me out at first. I had a protune and thought maybe it was bad. I remember asking the dealership and they had no idea what I was talking about.
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Old 11-01-2010, 03:20 AM   #32
Boosting 24
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it's most likely the tune pro making it jump
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Old 11-05-2010, 04:19 PM   #33
Chipper
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Default Jerky throttle

My 5sp 03 TS has EXACTLY the same symptoms as the other folks here are describing....and my 03 doesn't have drive by wire so I'm thinking that's not the cause.
This has been driving me crazy,(crazier), lately to the point of wanting to get rid of the car.
I'm really hoping the rear diff bushings are the cause,(as suggested by chimmchimm5)....sounds like an easy fix.
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Old 11-20-2010, 10:02 PM   #34
thumpetto007
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Well, part of it is also the AWD system. When letting off the throttle, the car tends to buck as shockwaves are transferred up and down the driveshaft.

I'm sure the DBW aspect only exacerbates (sp?) this condition, as would certain BOVs.
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Old 01-08-2011, 02:17 PM   #35
Special J
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Here's the problem.

What problem still remains?
Sadly, there appears to be one flaw in the DBW system that we do not have the tools to fix. The system appears to be unable to give a truly smooth transition away from idle. Significant testing with some VERY strange maps revealed that there is a small range just above idle that the system WILL NOT use. When you move the accelerator the smallest amount the ECU can detect, the engine instantly jumps from idle to an output about 70-90% above idle without passing the values in between. This is accompanied by a small lurch since the power doesn't come on smoothly. Dropping back to idle sees the same jump in the other direction. So, the bouncyness when trying to drive right above idle isn't totally eliminated due to this small gap in the programming. However, you can ease down to this point very smoothly, greatly improving drivability.

Everybody go paypal $10 to the Williaty Institute for ECU Research, and pray for a cure.
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Old 01-13-2011, 05:17 PM   #36
ChefVoltron17
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I think I'm a bit late on the subject but I have the same issues in an 07 wrx. As much as the DBW system might be at fault I can't see the jerkiness resulting from that. Even if the electronics aren't smooth, the car should be. I would be curious to know how many people with the STi group N engine mounts have this problem. Or better yet, someone with upgraded diff bushings, engine mounts, transmission mounts and shifter bushings. I've read plenty of places that stock subaru mounts are basically "rubber gummy bears".
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Old 01-13-2011, 07:09 PM   #37
WHOrU
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What Im seeing on mine live view accesport is at light throttle opening/closed throttle it appears the car cant make up its mind if throttle is closed or open and starts flipflopping air fuel ratios. generic coob tune this condition was much better. Custom tune the condition returned.
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Old 03-02-2011, 12:51 AM   #38
wrx_impreza02
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Try cleaning the inside of the throttle body, if you have a cool tech at your local dealer he may give you a can of it
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Old 03-08-2011, 12:46 PM   #39
gregoriousd
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I don't mean to threadjack, but I have something similar in my 06 2.5 automatic wagon (70k mi). If I let of the gas (mostly in stop and go traffic under 25mph) the rev's will drop fast from 1500ish down through 1000 and then back up to maybe 1200 rpm. I've always thought a healthy idle for a stock car is around 1000 rpm, give or take a little. If this is normal it's ok with me I can deal, however if this is some transmission problem staring at me from the shadows well...let's just hope it's not.
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Old 07-01-2018, 02:46 AM   #40
SergeDeC
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Quote:
Originally Posted by ChefVoltron17 View Post
I think I'm a bit late on the subject but I have the same issues in an 07 wrx. As much as the DBW system might be at fault I can't see the jerkiness resulting from that. Even if the electronics aren't smooth, the car should be. I would be curious to know how many people with the STi group N engine mounts have this problem. Or better yet, someone with upgraded diff bushings, engine mounts, transmission mounts and shifter bushings. I've read plenty of places that stock subaru mounts are basically "rubber gummy bears".
Once again, reviving an old thread here...
I am also experiencing the same bucking issue at low RPM in 1st-2nd gear (parking lots, traffic, etc.), on deceleration, and so on. I can confidently confirm that it has nothing to do with mounts and bushings.
I have a 2007 Impreza Wagon 5MT with the following parts installed and it still bucks just as much as it always has (Iíve had them all for approx. 30,000km):
- Group N STI engine mounts
- Perrin Pitch Stop mount
- Group N STI transmission mount
- TIC Rear differential bushings
- Kartboy Outrigger Bushings
- Kartboy Shifter bushings
I have also done the throttle body position relearn sequence on several occasions (when Iíve had my battery disconnected for more than 30min). That seems to smooth out the problem (very slightly) for only a brief amount of time, then it goes back to bucking.
My next attempt to fix the problem is to address the grounding issue. I still havenít decided if Iíll install a grounding kit or try to clean the current grounding points and coat them with dialectic grease for good measure (might try the latter and then resort to the former if necessary)...
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Old 07-02-2018, 12:54 PM   #41
lewisd
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Haha, I can't believe my thread's been resurrected after 11 years.

I sold the car years ago, cuz I was moving continents. I moved back eventually, and now I have a 2014 WRX Hatch (5-speed) that I love to bits.

Glad to see the someone fount the cause of the original problem I had, even if it's not fixable. Such a great car otherwise.

Quote:
Originally Posted by Special J View Post
Here's the problem.

What problem still remains?
Sadly, there appears to be one flaw in the DBW system that we do not have the tools to fix. The system appears to be unable to give a truly smooth transition away from idle. Significant testing with some VERY strange maps revealed that there is a small range just above idle that the system WILL NOT use. When you move the accelerator the smallest amount the ECU can detect, the engine instantly jumps from idle to an output about 70-90% above idle without passing the values in between. This is accompanied by a small lurch since the power doesn't come on smoothly. Dropping back to idle sees the same jump in the other direction. So, the bouncyness when trying to drive right above idle isn't totally eliminated due to this small gap in the programming. However, you can ease down to this point very smoothly, greatly improving drivability.

Everybody go paypal $10 to the Williaty Institute for ECU Research, and pray for a cure.
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