I have a 2002 pontiac gran prix gtp supercharged an have had high idol an car would shut off when slowin down.i have replaced idol control sensor,mass air flow,coolent sensor an now have sputter badly


Asked by Nov 19, 2013 at 05:43 PM about the 2002 Pontiac Grand Prix GTP

Question type: Maintenance & Repair

9 Answers

Tom Demyan

Look for a vacuum leak, and clean throttle body.


I have found no vacuum leaks an its fuel injected so no throttle body.ive been all threw all an cant seem to find the problem..need help....


Have you had the upper and lower intakes done. If not, as Tom said, you've probably got a vacuum leak from a failing intake gasket. These 3.8s are notorious for that. Look for white milky "goop" on the oil dipstick as well. A sure sign the gasket is failing. HTH. -Jim


No vacuum leaks its been checked an no milky goop on the oil stick.i was told maybe it is the egr valve? But i took the egr off an cleaned it like i was told but it didnt help any.

1 out of 1 people think this is helpful.

Is your service engine soon light on? If so have the computer scanned and post the trouble code(s) here. Advance and Autozone auto parts stores will do it for free. I doubt it's the EGR valve. With a faulty EGR valve it will either idle very poorly or won't stay running (valve stuck open). HTH. -Jim


My light is unhooked or something it has never came on at all an i took it to advance auto an they scanned it an its showing now the problem is the fuel injector 3 bad an is still showing all the new sensors i put on the car are bad..i just dont understand..sorry im a woman an tryin to do this alone an im not mechanically inclined..thank you for helping me

1 out of 1 people think this is helpful.

Oh my, that doesn't sound good. Honestly I think it's time to let a shop take a look at it. Sounds like some serious computer stuff going on here. -Jim

Wade Frazier

I would have said injectors... Sounds like it needs some serious TLC... How long have you owned the car? Are you looking to keep it?


check the fuel pressure regulator. That is exactly what mine did. look for raw fuel sucking into the throttle body through the vacuum line coming from it.

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