My 2006 2.2l HHR turns over too smoothly as though there is little or no compression but occasionally backfires. I don't know how to check for spark or if it's getting fuel. Suggestions? Help!
​​​​​​The check engine light came on a while back and the car would have a VERY rough idle several times but that light hasn't come on lately.

 

Could be bent valves from a timing chain issue. Then again it could be a bad ignition pack.
I suggest you don’t try to start it any more as you coul severely damage s piston.
If your handy you could take off the valve cover and look at the timing chain checking for slack!

 

Sounds like your timing chain jumped a couple of teeth and you have blown that engine.

 

DANGER, DANGER Will Robinson!!!!!!!!!

ANY backfire in todays engines is verrrry bad news.

 

I’ve discovered, it’s best to take the time to inspect the engine, as turning it over and trying to start it will only cause further damage, removing the cylinder head to replace the valves and replace the head gasket and timing and balance shaft chains along with the water pump isn’t a very hard job. With a few specific tools , I like to tear down the engine to visually infor damage to the pistons and cylinder head, it’s possible you only have a few bent valves, but don’t order any parts until you are sure what you need and determine the extent of the damage if any!