I'm a little confused. I was driving yesterday(97F150 5.4l) and the truck shuddered and check engine light began flashing. Went home, scanned it and came up with P0307 cylinder 7 misfire...which made sense. Reset the code and started driving(had some stuff needed done). The truck has been through several start up cycles and continues to miss occasionally, however there has been no codes(or check engine light) return. Should it not have stored the same code again after perhaps 3 warm-up cycles and maybe 10 key on cycles?

 

Might just mean that the misfire isn't severe enough (yet) to trigger an MIL. Swap #7 coil with a known good and drive it until the check engine light comes on again, and see if your misfire changed locations with that coil.

 

It may be the coil to plug boot. Very common. I would suggest you change them all.

 

Pulled the suspect coil last night. Secondary resistance was different than the new coil; changed it out...runnin purrrrfect again. Thanks for the ideas guys.