King4x4

I had the same problem. Took it to the dealer they changed all the sparkplugs(to the new motorcraft one peice plug that doesn't have the break off problem) runs like new. They also ran some kind of carbon cleaner through my engine.

ghost83

mine is doing the same thing 05 w/ a 5.4 3v only does it at 35-45 mph code only says bank 1 or it says misfire on start up (which it dont) and when it idles it sounds like a diesel any ideas on that one?

06KRF150

Just to keep you guys updated, the dealer found the coils for cylinder 1 and 5 bad (I just put cylinder 1 coil in a few weeks ago) so i had them replace both with plugs. When I pulled out of the dealer it did it again but not as bad but over the weekend it stalled on me once which its never done before and the next day it misfired again and the check engine light started flashing but then went out. I didnt get to check the code because I dropped it off at the dealer agian but they said its a problem with cylinder 4 again. Now they want to put an injector in since the coil is new.

firefighter

My 04 fx4 has a similar problem in cylinder 8. Except mine is also telling me it's to rich! I took my battery cable off with the ignition on to reset the computer I have not had a problem since! But I know it didn't fix anything!

OldMansTruck

Whenever i get on it hard it'll bog then once i get up around 80-85mph or higher the check engine light will flash and sometimes go off and somtimes stay on. Just had the code read and it was cylinder 8 misfire. Oh the joys of a truck with problems i didn't cause....