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Pontiac Repair/92 Firebird Engine light corresponds to cooling fan/rough idle


Hi Todd, you tried to help me back on 10/23 with this issue. I have noticed that when the cooling fan comes on the engine light comes on and the rough idle begins. To the point the car will die if I am not right there. When the fan cuts off, the light goes out and idle smooths right out. This is the 92 Firebird 3.1V6. None of the auto stores in my area carry a reader to extract code. Thanks for your help.

Hi scott. there are 2 things that could be happening here you could have a bad coil in the a/c compressor and for some reason when the compressor cycles the voltage spike is causing the light to come on. Or the extra load from the a/c being on is cuaing the isle to run lod and for some reason it'as cuaing the code. it could be ideling so low it's setting MAP codes or maybe you have an idle control motor that is slow to respond to the command for an increased idle speed. You may want to try cleaning the throttle plate and the idle control motor if they are crboned up that could be part of your isue.

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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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