I have a 4.0 engine that was runinggood before the head gasket went . Resurface the head and had the Vales done . Put back together and started to misfire on to cylender . Pulled the coil pack off turn it over and put the spark plugs in , hooked a wire around them and turned the engine over the first and last one didn't fire . Baught a new one and it did the same . So I put in a new cam sensor in it and no Change . No getting any code from the computer or any check engine light .