ATB Starving for Fuel, Throttle Response Non-Exisitant

[Cecil_Stringer]

Hello all, I appreciate the help in advance.
The target vehicle is a 1995 F250 4x4 7.3L with a 5 speed manual tranny with 260,000 miles and dual fuel tanks.

Yesterday morning it was a little hard to start.
Driving into work maybe 2-3 miles from my house it just feel in it's nose.
While the truck was running I held the gas pedal to the floor and it would not respond.

I pulled over, turned it off and popped the hood. Nothing appeared to be amiss.
After a couple of minutes, I started the truck up and it went back to what appeared to be normal. In neutral I could rev the engine as expected.

Driving into work it started to deteriorate and begin a feel as though it was having a fuel issue, not getting it or not using it if it was getting it. No anomalies in the exhaust were noted, the smoke remained black, not white.

It deal feel as though I may have lost brake pedal pressure, but that may have been in my head.

On the way home it started having issues again.
The issues are especially noticeable at lower RPMs, when keep the vehicle in the higher RPM ranges it appeared to function better, not great, but better.
However, even in the higher RPM ranges, the throttle response is noticeably sub-standard.

It would struggle horribly to take off from a dead stop, that is the most noticeable scenario.

Eventually it stopped running and I was towed off the road into a parking lot.

I treated the fuel with Diesel 911 and replaced the fuel filter.
It started back up and sounded like it was good to go.

On the last mile or so I ran the truck hard to see how she would respond, like a champ.
Until I got out of it, and it went back to starving for fuel and barely made it home.

Thoughts?
Suggestions?

Any help is appreciated.