Yes, I think that is the route I am gonna go. I changed the regulator recently...no change. But if everything is bypassing into the front tank, it is possible that there isn't much pressure there in the first place.

I'll just have to run the front tank out and replace it fist and see how it goes.

 

Since the truck sat for years I would approach this methodically or you will be chasing your tail. Been there done that. My 2 cents:

1. Get a Haynes manual. Good to excellent telling you where things are and how to properly diagnose.

2. Start by examining the basics first. Plug wires, fuel filter, cap, rotor, plugs etc.

3. Do a Sea Foam procedure. Since the truck has been sittin awhile, this would be what I'd do first.
Hope this helps.

 

The Haynes manual is what I have and it is what lead me to fuel pressure regulator. But if the front fuel pump is just allowing everything to pass right back into the front and rear tank, it may never be building up enough fuel pressure to work at an optimal pressure. But that is what it does when you pull out of the rear fuel tank, it dumps it back into the front one.

 

Also check for codes.i have a 89 with the 4.9 and the coolant temperature sensor was bad and it was sending to much fuel because the brain was seeing a cold start and would flood out.

 

Good point. I need to get the code reader out and spend a few hours doing some checks. If I only had a little more time to do it.