What is causing subaru backfiring severely after head job done?
Blew heads on '02 subaru. Had replaced. After job done car starting backfiring severely. Severity increases when under load, especially when using air conditioner. Threw code saying third cylinder misfiring? Guy who did job said it was first, the plug. Nope. Then said it was the plug wire. Nope Is still doing it and getting worse. I think it's the cylinder itself. Any ideas what else it could be?