Hello all to quickly summarize my issue.. I had blown the head gasket, heads went to machine shop put it all back together with new spark plugs start it up did not idling right had a little miss drove good just idled bad. Check engine comes on giving code PO303 so changed the ignition wires. Ran really good next day check engine on yet AGAIN now 2 codes PO341 and PO300. It is driving me crazy someone please help!