I just test drove the van with the fuel gauge hooked up and the needle
swept between 50psi and 70psi when I accelerated. The pressure never
dropped below 50psi even while the van was running poorly.

I also drained the gas and re-changed the fuel filter and it did not
help.

I will try and better explain how it is acting.

The van always starts and runs fine.
It drives fine for a short distance then starts to run very bad,
sometimes backfires, stalls, and completely dies.

It takes as much as 10 to 15 minutes of regular city driving to cause
these symptoms or 2-3 minutes of driving under a load (when I hot rod
it).

If the van completely dies, I can turn it off for 10 seconds then right
back on and I can usually baby it home (1-2 miles). If I leave it off
for 15 minutes it usually runs quite a bit better.

I have replaced:
Leaky CPI (spider)
Inlet outlet fuel lines (nut kit)
Fuel Filter
Fuel Pump and strainer
Exhaust from O2 sensor back (waste of $$$... my dumb fault)
Drained the gas

Is it time to take it to a mechanic? I am out of ideas and do not know
what else to check. Is there a certain test that a shop could perform
that would tell me what is wrong such as a general diagnostic or run it
on a computer?

Does this still sound like a fuel delivery problem?