I have a 2003 Pontiac Grand Prix with only 32,000 miles and has been meticulously maintained. I am experiencing engine stalling both while driving and at rest. I have taken the car to both a diagnostic center and the GM Dealer and neither one can isolate the problem. I have replaced the fuel filter, the Throttle Pressure Switch, and the Idle Air Control Motor. When placed on the diagnostic computer there are no error codes and the car runs well until it randomly dies. I can sometimes recreate the problem when I climb a hill at about 35 MPH and when I reach the top release the accelerator and the engine will die. I can kick it into Neutral and it restarts right away. Sometimes, after driving it, it will be slow starting requiring a longer than usual starter crank. Does anyone have any ideas about possible causes?
Is this one turbo charged?
After above is answered are there any warning lights kicking off?
Sounds like a leaking fuel pressure regulator. pull the vacuum line going to it and look/smell for fuel. If fuel is present regulator is leaking.
No. It is the basic 3.8L V6.
No. Only the usual lights when the engine is dead.
This may be a repeat answer since I jumped to this one before replying to the others.
This sounds like a good suggestion. Where is the fuel pressure regulator located?
It’s on the engine in the fuel rail. Has a vacuum line attached to it. About 2 inches in diameter.
I took the car to a mechanic that had scoped out the car before for this problem and asked about the fuel pressure regulator and claimed that if the regulator was faulty then the car would be smoking from too much fuel. Does that sound right? He wouldn’t even check the vacuum line as you suggested.
My thanks to Pete Peters. He was right about the problem being the fuel pressure regulator. I have been struggling with this problem for eight months. I took my car to several different mechanics including the Chevrolet dealer since there are no longer any Pontiac dealers. I asked them all about the fuel pressure regulator and they blew that off as not being the problem. The Chevy dealer suggested that I continue driving it until it got bad enough to figure out what the problem was. All told I spent over $600 trying to get this problem fixed. It seems that if you can’t get a computer error code then most mechanics have exhausted their knowlege base.
I’ll borrow a line from an old joke to summarize. “Why do so many mechanics today have strong shoulders and flat heads?” Because when you ask them a question they shrug their shoulders and when you tell them the answer they slap their foreheads in surprise.
Pete, that joke definitely does not apply to you.
Thanks, again, I just wish the mechanics had listened to your sound advice, and I would have solved this months ago and saved nyself a lot of money.
Fine Job, Pete Peters.
Yeah that guy talking about smoking from a pressure regulator must have been smoking himself. On my Olds, once in a while it would stall when decelerating and no other symptoms but it was the pressure regulator.