My '02 Ford Escort is throwing a P0304. Thus far I've changed the spark plugs even though the old ones were still in pretty good condition, alternated the plug wires between cylinders 3 and 4 to see if the misfire would move to cylinder 3 which it didn't, put a different coil pack on from another car that uses the same coil pack and I'm still getting an intermittent P0304. Only other thing I can think of that could be causing the problem now is a bad fuel injector. Does anyone have other ideas? 9+ times out of 10 the misfire happens on start up and lasts less than 30 seconds. Sometimes it will go for several days without acting up then misfire on every start up for a day or two. I've also noticed that since the weather has cooled down in this area that it's not happening quite as often. P0304 is the only code I have. The engine is the 2.0L SOHC. I had a cam position sensor code about a year ago so the cam sensor was replaced at that time.