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Discussion Starter · #1 ·
I have owned my 09 Impreza WRX for just under 2 years. A year after buying it with no problems, I was driving when all of a sudden the engine/cruise control lights came on and the car started revving at 2000 RPM on its own. The throttle was dead I could not accelerate or do anything. I turned the car off and turned it back on and it began to rev at 2000 RPM again. I left it to rev and then it began to rise all the way to 4000 RPM which is where I turned it off.

I let it settle for 2 minutes and then turned it back on. It turned on and drove fine however the engine light stayed on. The next morning I started it and the engine light was gone. Since then it has done the same thing again a few times over a few months and I have reprogrammed the ECU, changed the throttle body and cleaned my MAF sensor. Between doing all these things I was still having the same problem so it is still not solved.

My mechanic is hinting towards the throttle pedal but I wanted to know if any body has any clue what this might be? Seems to be an issue no mechanic can pinpoint the exact problem to. Have been to 3 mechanics about it too
 

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Make sure you don't have a mat on the pedal.

For this to happen something would need to open the throttle plate. Or you would have to have a leak somewhere past the throttle body with a fuel source open. Unlike a diesel that can run away gasoline engines usually can't. I'd suspect the pedal or the throttle body
 

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Discussion Starter · #3 ·
Make sure you don't have a mat on the pedal.

For this to happen something would need to open the throttle plate. Or you would have to have a leak somewhere past the throttle body with a fuel source open. Unlike a diesel that can run away gasoline engines usually can't. I'd suspect the pedal or the throttle body
Mat definitely isn't on the peda.

I've changed the throttle body so i've ruled that out. If it was the actual throttle pedal, would that cause it to rev uncontrollably? When its happening, even if i press on the throttle it doesn't pick it up, it becomes dead. It will just keep revving by itself. Also, the pedal mechanism is just the few bolts and plug right? That would be an easy fix for me to try myself.

It happened once then a few months after again, and now it has happened 3 times in the space of 2 weeks so its just completely random.. Can't seem to find a pattern
 

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Anything drive by wire is easy to swap. Remember the Toyota runaway Prius fiasco? The pedal can send errant signals.
 

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Discussion Starter · #5 ·
Anything drive by wire is easy to swap. Remember the Toyota runaway Prius fiasco? The pedal can send errant signals.
Sweet man I’m gonna get the pedal replaced sometime this week and we’ll see how it goes
 

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There are scan tools you can buy that can read the sensors and verify before you spend the cash.

Or an accessport can
 

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Discussion Starter · #7 ·
Anything drive by wire is easy to swap. Remember the Toyota runaway Prius fiasco? The pedal can send errant signals.
I got it scanned it was coming up as TPS (throttle position sensor) which is part of the throttle body. Considering I have already changed the throttle body, the accelerator pedal should fix?
 

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I would check the transmission switch. Dont know much about it but I know the drive by wire uses that switch to maintain rpm between shifts. Try pushing in the clutch say in 2nd or 3rd without removing the car from gear and you can see a similar behavior your describing. Never saw mine go to 4000rpm but definitely increases rpm in an unusual. Actually I thought something was wrong with my throttle body. Dumb design but if I throw it into neutral rpm drops normally.
 

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Discussion Starter · #9 ·
I would check the transmission switch. Dont know much about it but I know the drive by wire uses that switch to maintain rpm between shifts. Try pushing in the clutch say in 2nd or 3rd without removing the car from gear and you can see a similar behavior your describing. Never saw mine go to 4000rpm but definitely increases rpm in an unusual. Actually I thought something was wrong with my throttle body. Dumb design but if I throw it into neutral rpm drops normally.
I don’t think that’s the issue because my car drives normal when the problem is not happening. But when it does happen the pedal becomes dead and the car just revs at a constant 2000 RPM and then if I leave it long enough without turning it off it will start rising to 4000 RPM.

I am getting the accelerator pedal changed today. If the problem stops then that’s perfect. If not the throttle body, not the pedal then the next thing I’ll do is take your advice and look at the transmission switch man.

knocking out the possibilities one at a time so I don’t sell her :(
 

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I don’t think that’s the issue because my car drives normal when the problem is not happening. But when it does happen the pedal becomes dead and the car just revs at a constant 2000 RPM and then if I leave it long enough without turning it off it will start rising to 4000 RPM.

I am getting the accelerator pedal changed today. If the problem stops then that’s perfect. If not the throttle body, not the pedal then the next thing I’ll do is take your advice and look at the transmission switch man.

knocking out the possibilities one at a time so I don’t sell her :(
Thats weird man! Hope the pedal solve it all! Also those parts shouldnt be cheap to replace thats bad.
Good luck
o7


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