2003 5.4 f250. rainy day, engine started running with miss, check engine light came on and code is p0354. miss fire in #4. I changed all the plugs and #4 was dirty. started engine and still missing. while running I pulled the connector off each coil one-at-a-time. #4 makes no difference. switched coils from #1 to #4. tried pulling connectors again. #4 still not firing. put volt meter on connector with key on "on", no voltage on either side (or pin), but I see voltage on one side of other 7 coil connectors. I think that the coil is not getting what it needs from the wiring to the coil. how do I fix this?

 

Blast from the past...

Having the same issue with one of mine, p0354 code, replaced the coil with a new one....no change. Swaped the coil with a known good one... No change.

I'm suspecting a signal issue going to the coil. Where do I start?

 

Start with a close inspection of the wiring harness.

 

After 3 hours of trying different ideas, I started chasing wires and found a wire broke on the driver side about 2 ft from the computer.

 

Good job.