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Pontiac Repair/92' Bonneville


car idle's real high for about ten minute's . then when i hit the gas it goes down. then shortly after it reave's back up continueosly, back an forth. It's a 92'  bonneville SE 3800. I can't hear any vacuum leak's but the car is old? I'm not any expert but if fix thing's and i'm doing this for my grandma and i think it's something to do with the intake manifold vacuum. because it's never been changed?Please help me not look bad!

Hi James.
well with out a true scan tool there is just a few things you can do. It's either a vacuum leak a stuck IAC motor. you can use a can of carb cleaner and spray around the intake manifold and vacuum lines with the engine running is the idle picks up or sputters you found the leak. if not and it just has a high idle it could be a stuck IAC or an input to the engine computer that is out of whack like a Throttle position sensor. with out seeing it's it's just a guess. good luck :-)  

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Todd Puccio


General auto repair,electrical issues,driveability issues,anti-lock brakes,SIR systems,HVAC,engine performance,Gm specific. I have worked at my current dealership since the 1990 model year anything much older than that I have limited exposure to. I do not have very much transmission experience so those question you may want to ask of another expert. When you send me a question let me know the exact make/model/engine and year for the car or suv you have it makes it easier to answer the questions that way. If your happy with the answer I gave you please feel free to Donate. This is a free service to you and I am not compensated at all by this web site. I have 22 years of experience to share with you and my knowledge wasn't free to me. I had to pay for my education.


Experience in the area: I have been a technician in GM dealerships for over 22 years and I am a ASE master technician. I work at a Buick and GMC truck store Previously I worked at a Pontiac GMC store for 18 years. I Served a a lead technician when dealership was on a team system. I just recently moved to a Buick,Hummer,Saab Store when my franchise was purchased by this dealership. Organizations: ASE master technician


Education/Credentials:High school diploma,2 year vocational school degree 2 year college degree. Associates degree in applied sciences (auto technology)Awards and Honors: GMC master technician

Awards and Honors
Master GMC truck technician Master ASE technician in 9 categories

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