Can some one please help me .....i just bought a 1997 grand prix gt and my service engine soon light keeps turning on and off, it turns off for a few days then turns right back on again afew days later and whenever the lights on and i start the car after the engine has cooled and the car has been turned off for a while the idle will be way to high almost at 3000 rpms and after a few minutes i can turn off the car and restart it and it will idle normally and my acceleration will be a bit funny but whenever the S.E.S is off the car runs perfectly......so far ive been to 9 different mechanics and none of them can figure out the problem, any advice will be extremely appreciated THANKS

Get it scanned for codes (Autozone does it for free), write them down and post them here.

Just got back from auto zone. Got a diagnostic test ran and it produced this code PO121, im not sure what that is but some of tge things that ive already changed on the car=„ throttle body position sensor, idle air control sensor, map sensor, mass air flow sensor........one of the workers at auto zone told me that it could possibly be some loose wiring or a faulty ground, Im not to sure if that guy knows what he talken about .........soooo what do you guyz think this problem can be
?


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-- Thu Dec 01, 2011 12:52 pm --

I dont know what else it could possibly been trying fix this problem for a while now and still no success......has any one else here ever experiance this problem before?

-- Thu Dec 01, 2011 12:53 pm --

I dont know what else it could possibly been trying fix this problem for a while now and still no success......has any one else here ever experiance this problem before?

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1999 GT|SLP CAI|Borla Catback| Shift kit|18" Koblenz|GMPP Lowering|GMPP handling|Blk Headlights|ER Rcokers|HV3|HV TB http://www.fquick.com/The_Guz

Yeah, the code is for a TPS problem. There's a specific way to test it using a multimeter (the procedure should in the service manual ^^^^^^^^^^). You might even be able to unplug it and see what happens to your idle, just to rule out a wiring issue vs a sensor issue, not positive on how the engine will react or not though since I've personally never done it, obviously driving with with it unplugged is a bad idea though.

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Dubs:00 VW GTI VR6, Low and Slow 91 VW GTI 8v, Shave the Bay!! 91 VW Cabriolet 8v, bitch Basket
GP's:04 GP GT, Past now G-Ma's Girlfriend's 97 GP GT, "Project Pink Power"

I realize this isn't the same vehicle. But, I have a ford focus with the same error code and it's TPS AND IAC related. I need to test it for voltage but "boy toy" hasn't stopped over with his diagnostic tools to run the tests

Get the voltages checked, if they aren't right you probably have a short to ground or a failing IAC... then again I don't know enough about 3800's you may have something similar to an IAC or may not have one at all... perhaps someone else can help with that. I just know how to go about diagnosing it

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Gt2256v, FMIC, Port & Polish Head, Stage 2 Colt Cam. Rosten Rods, PD150 Pistons, Oil Cooler, Fuel Cooler, Diablo W/M kit, Built 5 speed with LSD
I work on enough GP's to know I don't want to own one =P

Yeah, there's an IAC valve, right above the TPS actually. Try unplugging one at a time and see what happens.

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Dubs:00 VW GTI VR6, Low and Slow 91 VW GTI 8v, Shave the Bay!! 91 VW Cabriolet 8v, bitch Basket
GP's:04 GP GT, Past now G-Ma's Girlfriend's 97 GP GT, "Project Pink Power"