Engine RPM increase out of my control
05-23-2011, 04:36 PM
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Engine RPM increase out of my control
Greetings,
I am having a problem with my 05 cobalt that I am trying to figure out. Last week it went into Limp mode a couple times at random when I was driving into work. I pulled a p0068 and a p0420, the p0420 I have had for a while now. I checked for vacuum leaks and cleaned the MAF and throttle body but didn’t see other problems. Now when I am driving when I lift off on the accelerator the throttle seems to stay at that same speed and the car will continue to accelerate at that speed and acceleration for a few seconds before dropping. Also when coming to a stop, clutch pedal in, foot off the acceleration pedal and applying the brakes the engine RPM will rise to about 4k and hold at that rpm until I rev the engine and sometimes a couple of times to get it to go back to idle. The car runs fine otherwise and this has been happening a couple times a day.
Has anybody seen this problem before? What should I be looking for? Would it be worth it to have the snapshot data reviewed for the possible cause before I start replacing parts? Thanks for your help guys!
I am having a problem with my 05 cobalt that I am trying to figure out. Last week it went into Limp mode a couple times at random when I was driving into work. I pulled a p0068 and a p0420, the p0420 I have had for a while now. I checked for vacuum leaks and cleaned the MAF and throttle body but didn’t see other problems. Now when I am driving when I lift off on the accelerator the throttle seems to stay at that same speed and the car will continue to accelerate at that speed and acceleration for a few seconds before dropping. Also when coming to a stop, clutch pedal in, foot off the acceleration pedal and applying the brakes the engine RPM will rise to about 4k and hold at that rpm until I rev the engine and sometimes a couple of times to get it to go back to idle. The car runs fine otherwise and this has been happening a couple times a day.
Has anybody seen this problem before? What should I be looking for? Would it be worth it to have the snapshot data reviewed for the possible cause before I start replacing parts? Thanks for your help guys!
06-02-2011, 08:29 AM
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well i hope you used MAF sensor cleaner to clean your MAF sensor, theyre very sensitive. and when you cleaned your TB i hope you didnt make the same stupid mistake i did. Cobalts have an electronic driven TB, not wire, so you cant move the plate in the TB. i moved mine to clean it and i have the high RPM problem. you can try the idle relearn procedure....
1. disconnect a battery terminal for like 5 mins, then connect it.
2. start your car and let it run for 3 mins
3. shut your car completely off for 1 min
4. repeat steps 2 & 3 two more times (you should start and turn your car off a total of 3 times)
hopefully this works for you, it didnt work for me and i had to take it back to the dealership to get my Engine Control Module flashed. Not covered under warranty and cost me $98 with tax.
good luck and let me know what you find out!
1. disconnect a battery terminal for like 5 mins, then connect it.
2. start your car and let it run for 3 mins
3. shut your car completely off for 1 min
4. repeat steps 2 & 3 two more times (you should start and turn your car off a total of 3 times)
hopefully this works for you, it didnt work for me and i had to take it back to the dealership to get my Engine Control Module flashed. Not covered under warranty and cost me $98 with tax.
good luck and let me know what you find out!
06-02-2011, 08:39 AM
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yes i had just had this same problem happening to me,
it ended up being a sensor, it was my barametric pressure sensor.
its only going to get worse and worse with every day that goes.
some days my car was fine other days my car wouldnt be able to get out of my drive way.
it ended up being a sensor, it was my barametric pressure sensor.
its only going to get worse and worse with every day that goes.
some days my car was fine other days my car wouldnt be able to get out of my drive way.
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