I have a 99 F 250 7.3. It runs fine at idle even for a long time. When I drive around the block a couple of times it will start chugging and lose power and shut off. I have been mixing fryer oil with the diesel. I changed the fuel filter, oil change, crank sensor and fuel pump. I added 15 gallons of diesel and diesel treatment. Pulled fuel filter and bowel is full I'm not sure where to look next.

 

You should probably put a fuel pressure gauge on it and see what it does at wide open throttle, under load.