19978 f-250 4x4 autu due fuel tanks all stock,symtom started with fuel filter light coming on during pull with trailer approx 10,000 lbs.Lost power died no restart,check filter seemed ok,changed and got restarted long crank runs ok until put under load.probelm reoocurrd did n ot restart.suspect mechanical pump.Replaced pump drove approx 250 miles same failure.Replace second pump check pressure under load drops,check all lines no leaks or restrictions,replace pump same results,check regulator looked ok,check screens in regualtor not clogged. replace filter base regulator assy have same results,occurs on both tanks,did check lobe on cam for pump eccentric looked good,mesured lift on lobe but can find no spec.going to drop and check tanks.

 

Welcome cfitzpatrick, bummer on the problem, I`ve had similar diesel fueling issues and it`s frustrating to say the least. Help is in the 1994.5 - 1997 7.3L Power Stroke Diesel forum: https://www.ford-trucks.com/forums/forum170/
Though it`s a quiet check out your local KY chapter, meet some fine folks and make some noise: https://www.ford-trucks.com/forums/forum151/

 

Did u find anything when dropping tanks? We r having the same problem and are at a loss.

 

Welcome aboard!!!