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Pontiac Repair/2000 grand am stalls after halfway on temperature gauge

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QUESTION: I have a 2000 pontiac grand am with the 3.4l v6 engine. I noticed that once the temperature reaches midrange of the gauge it idle really rough and sputters til it stalls and shuts off, happens when parked or driving. It backfires every once in a while during this rough idle. After a little cooldown it can run til the temperature reaches the halfway point again... any help is greatly appreciated. I havent been able to fix or even find whats wrong.

ANSWER: Hi Edward:

well first off good observation about the temp is what causes this issue. When you say rough idel is it just rough or is it like it's only running 4 or 5 cylinders instead of all 6? If it seems like it's misfiring then chances are it is and you dropping out a cylinder or a pair of cyliners. there are 3 igntion coils that run 2 at a time so if you have an issue with a coil or an ignition module it will cut out a coil. eletronics and tempature don't get along well so the heat is causing the issue. the thing to do it to get it to act up and then see what cylinders are dropping out a spark check can be used the coils put the checker in line with the lug wire one at a time and see if your missing park on any of the cylinders. That is where I would start looking. There are other possable issues as well like a crank shaft sensor that is the trigger to make the igniotn system work. That can be a heat related issue as well Noty all that common on these engines but still a possability. good luck :-}


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QUESTION: rough idle to the point where the rpm is dropping and going up frantically the car backfires and as much gas as u press it slows down backfires and turns off, car will turn on after a while cooldown but if u try at the moment it will just crank and sputter or turn on and start jumping the rpm range, also if it was a misfire wouldnt a code reader pick it up

Answer
No a code reader ay not be of much help. these engines don't trigger codes very easy. the newer cars are very sensitive and set codes quickly. The fact that this is backfiring would lead to an ignition system issue like I mentioned before coil/module,crank sensor.

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Todd Puccio

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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.

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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

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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

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Master GMC truck technician Master ASE technician in 9 categories

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