2002 f250 5.4 250,000 miles... little history. its blown plugs both sides 3rd back on each. fuel pump shorted and fried pump relay, replaced entire board as they are soldered to it.. misc coil packs over the years. but...
a few weeks ago it started a chirping / squealing and misfiring on passenger side. it comes and goes but is steady under load.
back off the throttle and you can hear a click kinda whoop noise and everything is good....but push back on the throttle a little too much and its back. Ease away from a stop, get on a flat road everything ok... can go 70 or 80mph and no missing....no chirping. Hit a slight upgrade and it start start chirping and missing.
hot or cold. start the truck up and sometime noise...sometimes nothing. push on accelerator slowly and nothing. rev to 5 grand nothing. hit it quick and it will chirp. Sometimes it stay on ...sometime not
Seems to be just one cylinder is it a funked up coil pack or injector
I beat on my truck pretty hard and it sees 4500 every time its out haha. but its not a daily driver anymore and its mostly for offroad use. My 5.4 lasted till 300k driving like this and a failed oil pump finnaly took out a rod bearing. sorry to not help with the thread but im just sticking up for the 5.4 a little, they make most of their power above 3500 rpm. speakerfritz if you keep up the easy driving you will see 500k haha!
I guess i can help a little, Coils go out on me all the time because i get water and mud up in there and whenever i drop a coil my truck just simply runs bad. Lots of miss fires lots of bogging out under a load and some small back fires from fuel loading up in the cylinder and a smell of unburned fuel and a hot catalytic converter coming from the exhaust. The same symptoms can be found with a bad injector, but it can depend on what is wrong with the injector. If its leaking you will see similar problems to the bad coil like smelling unburned fuel and lots of little miss fires. If the injector has stopped working you will notice a loss of power and miss fires. Is the truck throwing any codes?