uncontrolled acceleration
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From: Minneapolis
uncontrolled acceleration
This scared the edit out of me.
Started out with under acceleration.
Seems to only happen when vehicle and outside air temp was 20 degrees F or lower. Problem happened about 4 times during the winter of 2007-2008. Problem at that time was only under acceleration. I would be driving down the highway at between 55 and 70 MPH. The truck would suddenly not maintain speed and would not accelerate. Pushing the gas pedal all the way to the floor would produce no response from the engine. Check engine light comes on. After a few seconds truck drives normally again. This scenario has happened 8 to 10 times.
Over acceleration. This happened twice on 1/13/09.
Again truck had been sitting outside all day. Started truck and all was normal for the first 5 or 10 minutes of driving. I was driving down the highway at a steady speed of 60 MPH.
With no input from me suddenly the truck accelerated very rapidly.
The transmission down shifted and the engine RPM jumped up considerably. In my panic I stabbed the brake pedal and was able to slow the truck somewhat. After accelerating wildly for about 1 to 2 seconds the truck then went into the under acceleration mode. Now pushing the gas pedal all the way to the floor would get zero response from the engine. This sudden over acceleration happened again about ten miles further down the road.
Luckily the roads were dry and there were no vehicles close enough to me to cause any crash.
Codes were P2121 and P2123.
I replaced the accelerator pedal position sensor and so far the problem has not returned.
Wanted to post to alert others of potential danger of over acceleration when APPS is failing.
Started out with under acceleration.
Seems to only happen when vehicle and outside air temp was 20 degrees F or lower. Problem happened about 4 times during the winter of 2007-2008. Problem at that time was only under acceleration. I would be driving down the highway at between 55 and 70 MPH. The truck would suddenly not maintain speed and would not accelerate. Pushing the gas pedal all the way to the floor would produce no response from the engine. Check engine light comes on. After a few seconds truck drives normally again. This scenario has happened 8 to 10 times.
Over acceleration. This happened twice on 1/13/09.
Again truck had been sitting outside all day. Started truck and all was normal for the first 5 or 10 minutes of driving. I was driving down the highway at a steady speed of 60 MPH.
With no input from me suddenly the truck accelerated very rapidly.
The transmission down shifted and the engine RPM jumped up considerably. In my panic I stabbed the brake pedal and was able to slow the truck somewhat. After accelerating wildly for about 1 to 2 seconds the truck then went into the under acceleration mode. Now pushing the gas pedal all the way to the floor would get zero response from the engine. This sudden over acceleration happened again about ten miles further down the road.
Luckily the roads were dry and there were no vehicles close enough to me to cause any crash.
Codes were P2121 and P2123.
I replaced the accelerator pedal position sensor and so far the problem has not returned.
Wanted to post to alert others of potential danger of over acceleration when APPS is failing.
Last edited by madhat; Jan 19, 2009 at 12:51 AM. Reason: S/L
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