I have a 2001 F150 4X4 with the 5.4. Upon start up it runs rough. After about 5 minutes of driving it runs fine. CEL comes on. I took it and had it scanned and it showed p0306 code. I have read the posts on this and have not found my exact sympton. I would think if it was the COP it would get worse once the motor warmed up. I has rained in the last day so it could be a moister problem. This does not happen all the time.

I have also read where the code reader shows #6 cylinder but it is actually another cylinder causing the misfire. I don't want to throw a bunch of parts at this and still not have it repaired. Any ideas?

 

Forget what your reading some other place.
Code 306 is cylinder 6 misfire.
Why do you not believe what the computer says?
At least remove the coil and it's boot, inspect the boot or replace it and check down in the well for water or other debree and inspect the spark plug for damage or porcelain cracks.
Good luck.

 

If all looks well as per bluegrass's suggestions
try swapping the coil with another cylinder to see if the
miss fire migrates with it
good luck keep us posted

 

Could they make it any harder to get to the COP's? No moisture so it ran fine today. Gonna hold off for now because I don't have the time.

 

Took the time today and changed the cop and plug. Looks much harder than it really is. So far it seems to have taken care of my problem. Runs better and has much better throttle response. Old plug looked decent. Was not wet and was a darker brown color. The top of the plug was rusted as was the spring in the boot. Not the best design for conductivity in my book.

 

Making decisions ahead of time is very often self defeating as your first position.
Glad you took the bull by the horns and got the fix.
Good luck.