Pontiac Grand Prix Hesitates- Flywheel Keeps Cracking

2005 Pontiac Grand Prix V6. SES check engine light. Computer codes P0300 misfire. Just been getting worse over the last few weeks. Did a tune up, spark plugs, wires.

My 2005 Pontiac Grand Prix has a check engine light on. It also hesitates a little bit. Had the codes scanned and came back with P0300 misfire intermittent on a few different cylinders. We did a tune up but did not seem to help. What can i do so i dont have to take it to a shop, thanks.

If the spark plugs and wires did not help, there is a PCM (Powertrain Control Module) programming update that may fix your problem. This update corrects random misfires road speed when the TCC is engaged. Expect to pay 1 hour labor charge at the dealer for this fix.

pontiac grand prix

1999 Grand Prix 3.1 Lt V6. Misfire on cylinder 3.
I have replaced the flywheel once already. Why would my flywheel on my 1999 grand prix keep breaking around the bolt holes where it bolts to the engine. Has broke 2 times now.I replaced the first one myself by the book. All bolts torqued. 2nd broke in less than 200 miles. Breaks while driving down the road 55/60 mph. Car has not been mistreated and shows no other problems. Please help.

There should be no reason that it keeps breaking. The only reasons that the flywheel usually breaks is due to stress to it, rusting, or over tightening/wrong attaching bolts. If it's the teeth that keep breaking, I'd look at replacing the starter because it is engaging to far or to hard onto the flywheel. If it is cracking in the center, then try new flywheel bolts and be absolutely sure that you're torquing them to specs.

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