This is for a buddy with no computer access. He has a f650 that he put a dodge motor in was originally a 175 hp cummins now has a 96 215hp. He say he is loosing power while driveing and if he pulls over and primes the fuel he is getting pressure out the bleed hole.Once primed hes good for about 15 miles then he has to prime again.Engine runs good when its first primed. He went to cummins to get a part and asked and the guy told him one of the injectors is letting pressure back through the pump.
Does this sound like its possible?

 

Sounds to me like a dead or dying lift pump. I'd change that first. They are only like $45.

 

what is he running for a fuel cap? does it suck Not needed? other things could be an air leak in fuel line, my 96 does that when I get a fuel leak which has always been the hose from the steel to the filter

 

well
it turned out to be a check valve between the strainer and the lift pump. Seems it had a piece of gum wraper foil had attached itself to the little ball and when he got going it would clog the line some and when he went slow it would drive normal. That was about 2 days of head scratching
thanks for the help