Question about 2002 Pontiac Grand Prix

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2002 grand prix

My car doesnt go over 40mph ive changed the fuel filter spark plugs and wires and the MAF what next. The car runs better when I unplug the MAF and the check engine light doesnt come on. HELP

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  • dhauser101 Sep 03, 2008

    My 2002 Grand prix presently will not go over 45 mph. I have changed the spark plugs, spark plug wires, fuel filter. I also took it to Advance Auto and they put it on their machine and it did not show any codes. The check engine/service engine light does not come on. This started app. 2-3 months ago and at that time it would not go over 75 mph it has slowly over this time reduced to now only going 45 mph. What do you think?

  • Anonymous Nov 20, 2008

    I am having this same problem....yet now that I have kept trying to drive it somehow the brake lights and blinkers will not work...not to mention the windows.

  • Anonymous Nov 24, 2008

    This happened to me a couple of month ago. It was the catalytic converter, about 250 to replace and seemed like a brand new car when replaced!



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It was the Cat. Converter on mine, Don't drive it like that too long as it will send exhaust back through the EGR Valve and burn a hole in the Intake Plenum....

Posted on Jan 31, 2009

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I just had the same problem. Check the catalytic converter. It took me forever to get over 30 or 40. Drove everyone in the road nuts. They initially thought it was the transmission. Not so, clogged catalytic converter. I got it tuned up and the engine runs fine. Wish I could sasy that about everything else on this lemon!

Posted on Sep 02, 2008


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It is your converter I had the same problem on my 2002 Grand Prix GTP...Danny

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