2000 4.0 TJ.
It all started with a P0304 cel. Replaced spark plugs ( talked me in to iridiums). Replaced coil rail when light came back. Performed exh valve inspection (per service bulletin). Valve rotation good. Verified fuel injector resistances (all 15-16 ohms) when light came on again.. CEL is back on with P0304 code (#4 cyl misfire). Sent full can of sea foam through intake also...don't want to pull the head if I don't have to... Not sure where to go next, but after reading several thousand different threads with several thousand different opinions, I was hoping someone has a working idea