A Backfiring PT Cruiser

04 Chrysler PT Cruiser GT.

So, I am waiting on my buddy to come out of the store for quite a while. I am sitting there the engine not cranked just the accessories on listening to music. So when my buddy comes out, I try to crank the car… No go. No Big deal I have jumper cables in the back so with the help of an employee we get it started after several tries. Thing is, its rough the engine is knocking and overall being noisy. Upon trying to pull out of the space I find that my top speed has recently become 25mph. Now this car has a system where it reports error codes to you so after some research I get P2302, listed online as ignition coil or sparkplugs. I have since replaced both and things have improved. I can now reach 50 mph. It is still slow as hell and I don’t know what else to do, any suggestions?

You need to check the wires going from your PCM to your coils. If you have access to wiring diagrams, these would be called your coil driver circuits. There are intermediate connectors between the PCM and coils as well, your problem could be there.