1989 F250 diesel. Last fall I changed fuel filter and installed electric fuel pump because it was failing intermittently on trips. This seemed to fix it.

Today, while driving back home with a load of firewood, it died. RPMs would drop and it falters and dies. Give it a several seconds, crank a while (reprimeing I believe) and it slowly starts. Runs for about 5 secs and dies. The fuel filter light is on.

Earlier in the day while moving the truck around while loading wood, it was sputtering a bit- like not running on all cylinders, but actually I think it was starved for fuel.

Also- I think the tank selector has never been right since I've had it. I think it is time to trace the fuel lines down to the tank selector valve, and blow the lines out with air. Remove selector valve and clean and bench test.

I don't know what else to do. Maybe the return lines?? Don't know if they would cause this fuel starvation.

Ideas?