I would say the high pressure pump. The in tank pump is mainly there to get fuel out of tank and to the frame. With that weak of pressure I would say high pressure pump is going out/is out. At least thats what I can think of right now, sounds logical in my head....but haven't had my coffee yet..so I could be way off.

 

The lift pump (rear) just keeps pressure to the main pump so it doesn't starve or vapor lock probably nothing over 10psi.

 

Thanks for all your help, I will change out the high pressure pump and report back. This has turnned out to be a very good thread of information. Now we all know you cannot use a tire gauge for the fuel rail. LOL! Another thing. When I first brought up my symptoms EdgeThis told me "check my fuel pressure at the rail." I did not listen. If I would have I would have saved a lot of money and time. I just want to say that if you come to this site for information, Listen to the advise given.

 

I changed the High Pressure pump last night. I must have two problems than just the pump. I now have pressure to the rail and the truck is running 95% better. For example: before if I drove 1 mile, it would cut out and jerk at least 50 times. Now it only cuts out and jerks 3-4 times in a mile. I noticed before the pump change that everytime it would cut out my battery gauge would fluxuate with the RPMs, as if it was losing electrical power and that was making it cut out. Last night I messed with wires dealing with ground, ignition, EGR valve and now my battery gauge is as steady as a new car. I think along with the high pressure pump (fixed now) I also have some wire short issues. Any thoughts?