I just recently purchased a 1994 f350 with the 7.3 powerstroke in it. Its basically stock no modifications with the exception of an after market airfilter. The problem I have right now is the truck will just cut and surge. Its done it 3 times now. The first two time it died once I came to a stop only to fire up again and run just fine. The 3 rd time the truck did not die once pulled over idled rough for a few seconds and cleared up. It spit out a little white smoke also. I'm sure its fuel related but her is the kicker, it only does it when I'm running on the rear tank. And it only seems to do it when I'm out of the throttle ie going down hill or letting off the gas to slow down.