REV HAPPY grand am

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I've got a 03 grand am w/V6. It will rev about 3500 rpm without warning. Sometimes it does it upon start up, other times it does it while driving it. Scares the bajeebuz out of my wife! Is there a sensor malfunction or what? Any help would be appreciated!! Oh ya, it won't quite until I shut it off and restart it!
 
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Is it setting a check engine light? Do you have code reader? If it were my car, i would call a tow truck and have it hauled to a shop i trust.
 
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when does it happen when hot or cold? Does the gas pedal stick sometimes? I have seen throttle bodies so gummed up that it would actually make it hard to open and close... How about a check engine light if it is electrical related that may help.. I would park it and figure it out Dont drive it.. Could it be a large vacuum leak? When car is Off does the gas pedal travel back and forth easily and with enough spring tension? Also i would not let it idle at that rpm for more than a few seconds you could do serious bearing or even wrist pin damage.
 
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Could be a TPS, they self calibrate every time you start the car. I would look at the computer data stream if you can, it seems like a sensor out of spec but not far enough out for it to realize and set a code. There are codes for "the idle isn't what I want it to be"... obviously the car wants it to be!! Part of the idle diagnostic chain includes seeing the throttle at zero percent, if the car perceives it to be open it doesn't care what the RPMs are.
 
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I had a Mercury Cougar that did that. The dealership never could get a grip on it. They kept cleaning the throttle body and replacing throttle position sensors under warranty, but the problem kept coming back, then it would go away, and come back again...
 
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On GM 3400, erratic idle can be fixed sometimes with the FM (F*** Magic) IAC reset procedure: Reset ECM by pulling ECM fuse (under hood) for a few seconds or disconnect battery for a few seconds. With A/C turned off, start car and immediately put it in Drive with your foot on the brake. If the car does not start initially, keep trying WITHOUT putting your foot on the accelerator. Let the car idle in gear for at least 5 and no more than 7 minutes. Shut off the car for 10 seconds. Start engine, place in drive and let idle for 5 minutes. Shut off engine. Idle is learned.
 

ridgerunner

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 Originally Posted By: crazyoildude
when does it happen when hot or cold? Does the gas pedal stick sometimes? I have seen throttle bodies so gummed up that it would actually make it hard to open and close... How about a check engine light if it is electrical related that may help.. I would park it and figure it out Dont drive it.. Could it be a large vacuum leak? When car is Off does the gas pedal travel back and forth easily and with enough spring tension? Also i would not let it idle at that rpm for more than a few seconds you could do serious bearing or even wrist pin damage.
It happens every couple of days. She has complained about it for a few weeks now but until today I hadn't seen it for my own eyes. Unfortunately, we are about an hour and a half away from home and have to drive it back. Good thing I'm driving!! No idiot lights at all. Gas pedal is fine/normal. It seems to idle fast sometimes when she stops at a traffic signal and not when driving down the road (thank God). I'll take it to my mechanic on Monday and see. I just wanted you guy's thoughts on this.
 

ridgerunner

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 Originally Posted By: carwreck
On GM 3400, erratic idle can be fixed sometimes with the FM (F*** Magic) IAC reset procedure: Reset ECM by pulling ECM fuse (under hood) for a few seconds or disconnect battery for a few seconds. With A/C turned off, start car and immediately put it in Drive with your foot on the brake. If the car does not start initially, keep trying WITHOUT putting your foot on the accelerator. Let the car idle in gear for at least 5 and no more than 7 minutes Shut off the car for 10 seconds. Start engine, place in drive and let idle for 5 minutes. Shut off engine. Idle is learned.
I'll give it a try!
 
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The throttle is probably not opening , but the idle air motor is. Actually, this shows it IS working, because it opens and shuts. The problem may be in the throttle position sensor as well as the IAC motor. Call a dealer to see if there are any recalls or service bulletins pertaining to this.
 

ridgerunner

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 Originally Posted By: carwreck
On GM 3400, erratic idle can be fixed sometimes with the FM (F*** Magic) IAC reset procedure: Reset ECM by pulling ECM fuse (under hood) for a few seconds or disconnect battery for a few seconds. With A/C turned off, start car and immediately put it in Drive with your foot on the brake. If the car does not start initially, keep trying WITHOUT putting your foot on the accelerator. Let the car idle in gear for at least 5 and no more than 7 minutes. Shut off the car for 10 seconds. Start engine, place in drive and let idle for 5 minutes. Shut off engine. Idle is learned.
Ok, can't find the fuse for the ECM. None of the fuses are labled "ECM". I do, however have a big friggin' sledge hammer handy just in case I need one!
 
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Look around, two fuseboxes at least: One under the hood, one in passenger compartment. Open front doors and look at the sides of the dash, newly visible.
 
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This procedure was copied from 60degreev6.com. The main fuse box is next to the driver's side shock tower. However, I am looking at the fuse box on my GLS and also do not see any fuse labeled "ECM"... So just disconnect/re-connect negative battery wire and follow rest of procedure. If your car has less than 60000 miles your problem might be covered under the "Emissions device" warranty even if you are not the original owner.
 
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