P0300 says possible cylinder head assembly

Question

Hi I have a 06 hhr that I have a code p0300 on I have changed all coil plugs an injectors but code still reads possible cylinder head at auto zone so is that the definitely problem I hope not.

Comments

Ok so how do I check all these this I can't afford to put in the shop and have been doing the work at home

Answer 1

HI there

This code is either for a multiple cylinder misfire or the computer can't determine which cylinder is misfiring. This can be brought on by a variety of things. With what you have done, I would next check for vacuum leaks, possible timing issues can also cause the problem. I would also check the fuel pressure to try and resolve it. Low fuel pressure can cause misfires as well.

Comments

So can I at least rule out the cylinder head. And doesn't that have a code of its own