P0300

[iversonhof]

I've searched this forum and other forums. A 2006 cobalt with 67000 miles completely plain no aftermarket stuff at all. I have a check engine light with code reading P0300. Is there certain things to check in a certain order? One thread I read said there could be up to 10 things wrong with the car with that code. I've seen coils, cat, to bad plugs! The car acts normal with just the check engine light on. The old owner said he purchased it at 16000 miles and the check engine light has been on ever since. Any help would be greatly appreciative.

 

[west40texas]

P0300 is Random/Multiple cylinder Misfire detected, could be coil pack problem, might try a pull a part coil replacement then clear error codes! All my misfire codes have always been because of coils or coil pack on 3 different chevy engines. Sorry no one has answered you here, I just registered to find out about an engine block swap, but does not look good about responses! Good luck !

 

[Bobber64]

I just bought a 2006 Ls coupe that had that problem. First I had cylinders 2&3 missfiring. Found that the ignition module was bad. Car came with a new coil assembly that didn’t fix the problem. I replaced the plugs and installed the new module. That fixed cylinders 2 and 3. Then I had cylinder #4 that was not firing at all. Did a fuel injector test with a snap on scanner and a fuel gauge to find that problem. I just replaced all of the injectors and it runs perfect.
Keep in mind that with a P0300 code you really need fix spark and fuel problems before chasing 02 sensor, canister purge, and others that pop up with a badly running engine.
This car had been sitting for around 10 years when I bought it.