I've been having an issue with my '08 HHR LS with 110k that I thought I would put up a post about for others that may run into the same issue. Sometimes the car would idle just a bit rough, and when I would accelerate hard like up a big hill, the car would literally jerk and partially loose power in and out. It wouldn't completely stop or anything, just loose power partially cutting in and out but still running. It wouldn't do this all the time, only sometimes, but it was always when I really had to step on the pedal. It also didn't matter what gear I was in. The last week however it got to the point that everytime I went up a large hill near my house and had to step on it, the car would do its random jerking thing. No check engine light and no codes came up ever.

After being stumped for some time due to the random nature of this, I did a lot of reading around and research online figuring that I either had a firing issue or a fuel issue. A firing issue made more sense to me. Others with similar problems online had coil packs that were the source of the problem, so I figured it might be a coil pack problem. I checked all of the coil pack boots, and they were clean with no carbon or cracks, so I replaced all 4 ignition coil packs with the idea that one of them is probably not quite putting out the proper voltage to the spark plug sometimes causing the plug not to fire properly. I was right. I replaced them yesterday and went zooming up a large hill smooth as butter. I got all 4 coil packs from ACDelcodirect.com for under $120 shipped. The original coil packs are ACDelco. I took a bit of an educated guess here, but it was cheaper to replace all 4 packs than to try to have the dealer do a diagnostic.

Maybe this will help someone else out there.

 

Thank you. Now through a process of elimination you can find the bad one, toss it, and save the others for spares.

Boydie Back in the Saddle