01 7.3l

[baddkarmaracing]

my buddies 01 wont run over 55mph and he is stuck about 200 miles from here
he told me a couple days ago that it wasnt building boost and wasnt running right but they continued to drive it even after i told them not to...
all he can tell me is the truck idles and revs fine but when you put a load on it it wont run right they are putting a fuel filter and deisel kleen in it as i type this but i would think there is something else wrong with it any ideas? im going to get them if it wont run after the filter change

[JSchuricht]

Check all the boots for the IC and turbo. Probably had one pop off or split.