Please help, truck will run fine for hours at a time and then it will start to run bad and won't make power at highway speed. I have changed MAP sensor,EBP sensor, EPR valve. The dealer replaced the ICP sensor and got codes P0476, P0603, P0605, & P1211. They said Turbo was making 18 LBS of boost and it should be fixed. Two hours after I left the dealer the problem came back. What do you think the problem is? Please help.
2001, 7.3, 122,000 miles.

 

How old is your oil? Fuel filter?

 

Sorry, I should have added, oil changed on schedule. I carry a extra fuel filter and the first time this happened I changed the fuel filter on the side of the road. It did not help. This problem has been very frustrating. The truck will run fine most of the time. The problem has only happened once without the trailer. The dealer still has the truck and is going to look at again on Monday. I live in Fl and broke down in Ga. Any other ideas?

 

Fuel pickup screens in the tank are getting clogged.
Fuel pressure drops off because it cannot keep up with the demand for fuel volume at highway speed and the truck falls flat.
Remove tank, clean out the screens and it will run good.

 

I agree that it could be a fuel delivery problem. I will have the screens checked and cleaned. The last two times that it happened was after 1-2 hour highway runs at 63 MPH, all was fine until I got off the highway and drove at low speed for a few minutes and tried to get back on highway. It would not accelerate or run at speed.