seems like this problem started when I replaced the valve cover gaskets
I took it in to get a diagnostic they told me it was the knock sensors and it would cost 1,800 that didn't take care of the problem took it to another mechanic he said it was a blown head gasket 1,500 . I took it a part had the head redone put it together and I still have the same problem miss fire on 2,4,and6.
what more do I need to do. This thing has drained my wallet.gaskets alone are't cheap.runs a little rough at idle and runs like champ when I drive it. not good on gas
can I get a little more help