P0304 code remedy?

[302bossman]

Just experienced a P0304 code #4 cylinder misfire (flashing, then solid check engine light) on my 2007 5.4 with 62k miles. Interchanged the coil pack with another cylinder and cleared the code but the code returned the same which one would think eliminates the coil pack as the problem.
Any other suggestions that I might try?
The spark plugs are fairly new (about 10k miles or so). Also, it seems the misfire is less severe when driven with o/d off and the engine taching higher.

Any help is appreciated!

 

[Swetrid]

I would check and make sure spark plug is still tight. We have seen a few come back with misfire in which the plug is loose.

 

[302bossman]

problem solved

Pulled the plug (replacement Champion single piece plug design) and replaced with an autolite plug and fixed the misfire.

 

[gears351]

I'd yank the rest of those champions out - just had the same issue with my 07 but it was a 0300 random misfire code - those "one piece design" champions were toast, less thank 10k on em too!