I just bought a cherry 89 F250 regular cab. Was two owner, 90000 original miles. Owned by an old man in Montana for use as a camper truck. No rust, everything works, new exhaust, just a dream.

Has a 460 and C6 tranny, 4wd.

The only issue is when I run on a front fuel tank it will run for awhile then cut out like I ran out of gas, so I have to keep the small rear tank full. I drove it all over yesterday and would run for awhile on the front tank, it'd cut out, then I'd switch to the rear, run it for awhile and switch to the front until it cut out again.

Fuel filter has been changed. Any ideas?

 

Front fuel tank pump inoperative.
It will run when switched to the front until it uses up the fuel in the selector reservoir or the selector part of the reservoir is not switching.
The HP pump is what is running the engine until the fuel is used up in the reservoir.