Quote:
Originally posted by Shadow248
Well this is an interesting one. As I said in another post, I have Mandi's SVX this week because she took my car home to get fixed. I have a 1996 Grand Prix GTP with the 3.4L V6. Here's the problem. Starting this fall, when i went to start the car cold, it would fire right up, but without me touching the gas, it would jump right to 3000RPM, then RPMs would fall fast until it stalled. I have to keep touching the gas to keep it running, and everytime i just barely touch the gas, it goes ballistic...3000-3500RPM...then right back down again to almost stalling. It does this until the engine warms to about 120 degrees. Then it's perfectly fine. Like i said i sent it home to get fixed, well the shop said there is NOTHING wrong with it. They ran a computer diagnostic and a "hand" diagnostic and they said it runs like new. GREAT. So i know i will get this car back and it will do the same damn thing it always did. But im sure it didn't do it when they checked it out.
So does anyone have any clue what could be the problem here? I am thinking i will try some injector cleaner to see if that helps.
My only other thought is...maybe this is an effect of the engine being accustomed to a higher octane fuel? Of course i bought it used and i have no clue what the dude put in it before me...so i put in 89 oct. If he put in 93 and i put in 89 now, could it have that effect?
Thanks for any help you can give.
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Try cleaning the idle air control valve. I could see how it getting stuck could cause your problems. My wife's Legacy exhibited a different set of symptoms, but I think the same problem might be the cause. My reasoning:
IAC is closed when throttle is opened. If you let off the gas and the IAC sticks shut, it could stall the car.
It's a guess, and probably not a good one, because it doesn't explain why your car only does this when cold and why your revs jump so much when you touch the throttle.* That right there leads me to suspect the throttle position sensor, which I doubt is cheap.
* No, wait, it might. If the IAC stuck open when throttle was applied, would the O2 sensor tell the car to add fuel to this now-lean mix?