Ok so yesterday we did a major upgrade to a friend's 2003 Rubicon 4.0(62mm throttle body, Bosch 4 hole injectors, rear cat delete, flow master muffler, and banks torque tube header) after install noticed a misfire in the engine checked for vacuum leaks also checked didn't find any vacuum leaks but still has a slight miss to the engine. Also checked plug gaps and they were all set to .35(they were at .45). Please has anyone run into this issue? Engine code is P0300 multiple misfires cylinders 1-6.