MY 2003 GRANDPRIX GT LOOSES POWER AFTER WARMING UP FOR 3-5 MIN BUT RUNS GOOD WHEN I FIRST START IT IN THE MORNING

Asked by Sep 11, 2013 at 10:25 PM about the 2003 Pontiac Grand Prix GT

Question type: Maintenance & Repair

So i have the 3.8L v6 in my 2003 grand Prix gt and i replaced the spark plugs in the car as well as the wires cleaned the coil pack plates checked the sensors and i still cant figure out why the car runs good when i start it up for the first time in the morning but after 3-5 min of warming up the car looses all its power feels like its running on 3 cyl but it runs smooth ( even when it looses power) until i put it in gear then it wants to shut off and die out, sometimes it stalls but for the most part it stays running just really rough like if the firing order is mixed up but its not,even when i drive the car down the street running like this it revs up fine does not shake when I am on the gas, but has no power what so ever i also cut the cat out thinking it was blocked but that didn't solve anything my car has 101k on it. Could it be the muffler blocked or the coil packs, or something else please help me out i drive my 2 year old son to school in it and i need it to run good and be dependable please and thanks

2 Answers

i had a van that did the same thing lost all power couldn't go over 30 mph it ended up being the catalytic converter.hope this helps.

35,675

Is the check engine light on?

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