I have a 2002 Ford Excursion 7.3 L Diesel. I have been having some trouble intermittently going up hills where despite the pedal being to the floor the engine runs extremly rough and starts shaking and starts to decelerate and lurch along. I decelerate to about 15-30 miles per hour. After pulling over and letting it sit it will start up and run a little rough at first but then go along. There has never been a check engine light. The fuel filter is pristine. This has happened puling a 5000lb trailer and when I wasn't pulling anything. I have been to 3 ford dealers. One changed my Pressure regulator and charged me 450 bucks and then 120 mile down the road it happened again. Another ran diagnostics and thought it was my pressure controller but when I told it that the other dealer said it ws fine and asked that he check the oil pressures he provided me with a read-out that said they were okay and charged my 200.00 for his time. He stated he didn't know what was wrong. A third ford mechanic has now looked at it and stated he doesn't know whats wrong because when he drove it it didn't do it. he again checked fuel filter which was again pristine and said that when he disconnected the fuel pump it was flowing strong. After arriving today to pick it up, and being told nothing was wrong, I have asked him to drop the tank to check the 3 screen there and the sock. Is there any other possible cause for this problem. The engine also seems not to like it when we are at 1/4 tank of gas. Any ideas?

 

Since everything else looks good in your fuel system, I think you need to do this: Welcome to guzzle's In-tank Hutch Mod Web Page

 

You need to do the hutch mod, using the link that was given to you. You could have a split in the line and it starts sucking air when you have 1/4 tank of fuel while truck is going up hill. I bet this is the problem.

Good luck.

 

3x In-tank mods