i have a 87 gta with a 350 tpi, may problem is sometimes when i drive my car the engine will idle way above where it should. at operating temperature in park it will idle at about 1400 rpm. i thought maybe it had a bad air bypass motor so i cleaned it out with a good air intake cleaner. that seemed to help for about two days. it idled at 600 rpm in park. but two days later it was back to 1400 rpm. this problem is killing me on gas mileage and it drives me nuts because i have to cram down on the brakes to stop at a light and hold the car still. please help.

 

I am assuming by what you said you mean you cleaned out the iac valve. Instead of just cleaning it did you set it though? And why don't you try taking it apart and cleaning it. There should be an article in the tech section about it i believe.

 

very interesting. My car has been doing the exact same thing. I have adjusted it correctly so I would assume the computer is getting bad information from somewhere. My idle in drive will be like 900 when it should be 700.

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'89 Formula 383 TPI

 

Is your timing too advanced?...do you have a vacuum leak at the TB maybe?

 

did you check the TPS(throttle postion Sensor) cuz that same thign was happening to me...but mine was worse whent he engine was cold it would idle at 3 grand...triyng to stop the car like that jsut burned up brakes....