I recently purchased an 04 F350 Crew Cab, Long Bed, 4x4 with 197K miles on the 6.0 (Late 03 build). Truck fires right up without any issue, but struggles when it's under a load. Problem seems to get worse when it warms up. I've already completed the following:

- Replaced EGR valve
- Replaced one bad injector that was triggering a code
- Oil and filter change with Rev-X
- New fuel fitlers
- New batteries
- Confirmed FICM has 48V
- Air test didn't find any leaks in the high pressure oil system

I recorded the symptoms, and you can see a video of what it's doing here:
Problem seems to come and go. Somtimes I'll drive it for an hour or more without any issues. Other times, I can't go more than a mile down the road before it starts missing. I also tried unplugging the EGR valve for a little while, and I have yet to have the issue with the valve unplugged. Issue occurs again immediatley after I plug the valve back in. Not sure what else it could be see I already put a new EGR valve in it.

Any help would be greatly appreciated.

 

So with the egr unplugged you dont have the problem at all and the truck runs good right. If it does then i would just buy the stc programmer and turn the egr valve off and leave it off till you do egr delete or bulletproof cooler.

 

on the early trucks like the 04 you can just leave the valve unplugged, had mine unplugged for 200k with no issues and no CEL like the newer trucks.

 

I didnt know you could that at all. I guess its the same thing as turning it off but i thought the check engine light would be on all the time.

 

Unplug it ad see, it sould only come on in 05 and up trucks.