I have a '03 F150 with 5.4. I have a misfire showing up on number 4, code P0304. I have changed COP, injector, and plugs, even tried moving number 4 COP to number 1 but still getting number 4 misfire. The miss fire only happens after the truck has set over night or several hours. But the real kicker is that it will clear up after a few minutes and runs great. Granted the truck has over 200,000 miles on it but this has just come up in the last month. I am pulling my hair out !!!! Any suggestions?