2008 Grand Prix
3800 NA Series III
140,000 miles

Received a lot of help in the past from this site, hoping to help someone else...

Back in January, I had the timing chain cover resealed, loosing coolant. When done, car wouldn't idle properly, they ended up replacing all 3 coils.

In April, daughter complained car running rough, she ran codes got a P0305 cylinder 5 misfire. When I got there with a coil in hand it was idling fine, she was at college 2 hours away, so I replaced the coil anyway.

A few weeks ago, she complains about a rough idle, but no code. She is home for the summer so I decided to do a deeper dive. I ran codes and now it is thowing a P0303, swap coil #3 coil with #5 coil, misfire stays with coil 3. Ran a cold compression test on front 3 cylinders, 140, 141 & 145, happy with those numbers. When I removed the sparkplug wire 2 of came apart, piece that snaps on the plug separated from wire. Checked plugs looked good, gap was within spec. started putting plugs back in and noticed the passenger side front/top motor mount was loose, checked closer, the mount nearest the ICM was broken, the other top bolt wasn't even there, and the header stud for the lower mount was snapped off. Also noticed the close proximity to the mount and the spark plug wires. Removed mount, called NAPA to get a new one ($75). In the meantime, replaced sparkplug wires, idle smooths right out. Next day get motor mount, install that, could only mount to top 2 bolts since header stud was snapped. I am guessing with that motor mount broken it rubbed the wires enough to get a slight short to ground or between the wires. Been 4 days and daughter has not complained about any rough idle, hopefully that was it.

Got to wonder, what happened to the motor mount, I am usually pretty observant and notice things like that. About4 years ago my daughter rear ended another car with some front end damage, replced hood, bumper, hood latch, headlights and plastic panel behind headlights. Quite possible it happened then. Possible it happened during the timing chain cover reseal. Impossible to know for sure.

At this point, motor mount attached with 2 top bolts, figure risk of those breaking with the lower is less than me breaking the header stud in the head when trying to replace.

With the car being 14 years old and 140,000 miles, I just need this thing to get my daughter through her last 1.5 years of college and then she can buy her own car.

Thanks for the help in the past, hopefully this helps someone.

John