I have literally changed everything know to man in an attempt to rid myself of this P0301 misfire code. The only thing left was a compression test. Guess what. Cylinder 1 was 125. all the rest were in the 160s. So I pulled the head. The number 1 exhaust valve was recessed in the seat!! All the other valves stuck out 2mm or so. also the face of the valve compared to #6 indicates it isn't sealing. Interesting......