I have an '06 with the 5.4, about 80k. Occasionally, when the engine is cold and I get on it (such as merging onto highway) I get random misfires. This has been an sporadic problem for several years, but it is particularly bad in the winter (DFW, so we're talking 30s and 40s) It's also accompanied by rough idle.

I have had a few coils and plugs replaced over the years when my ECU reported specific cylinders misfiring, but it didn't make much of a difference. I also get the error "misfire on random cylinder". Air filter is clean, fuel injector cleaner every 6 months or so. Don't know where to go from here.

Any advice would be appreciated.

 

Moved to 04'-08 Section.

 

Mine is doing the same...hate it

 

have you replaced the isolater boots on the coils yet? thats where i would start.I highly recomend you use the motorcraft if your dealer stocks them if not I have used the ones from napa and they are ok. and also that you do all 8 of them at the same time. while you have them out make sure there is no moisture,oil or crud in the plug holes. blow them out with some compressed air and brake clean if needed (ps-wear glasses) .