Summarizing

Fuel/Ignition/Other? Please help

I have been trying to figure this out with no success. Can you guys
take a look and offer any suggestions you might have?


Vehicle:
1995 CHEVROLET TRUCK ASTRO VAN
2WD Automatic Transmission
6 Cylinders 4.3L CPI
105,000 miles

Symptoms:
The van always starts and runs fine for at least a minute or two.
However after a short distance it will not accelerate properly and it
will try to stall. As it progresses I might get some popping at the
engine and eventually it will die. When I press the accelerator it
acts like it wants to die.

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). It does not seem to be directly related to engine temperature.

If the van completely dies, I can turn it off for 10 seconds then right
back on and it definitely drives better (not completely normal). If I
leave it off for 15 minutes it usually runs quite a bit better.
Overnight and it runs normal when I first start it.

Parts Replaced:
Leaky CPI (spider)
Inlet outlet fuel lines (nut kit)
Fuel Filter
Fuel Pump and strainer
Exhaust from O2 sensor back
Drained the gas
Ignition coil
PCV Valve
Tune up (plugs,wires,cap,rotor)(6 months ago)
Oxygen sensor (6 months ago)


Current Diagnostic (I am a complete armature so some/all items could be
irrelevant)

EGR (sticking)
Tapping/ticking started after I removed/checked this. I am pretty sure
I just need to take it off again and clean or replace. I do not
believe this is my main problem because I took it off, closed the
valve, and reinstalled without hooking it up. This test did not change
any of the symptoms listed above.

Distributor
I just examined the distributor and one of the plug wires and probes on
the distributor was severely corroded; the rest were fine. I will get
a new cap and wire tonight and check the plug.

Fuel Pressure
Test with a fuel pressure gauge. After sitting overnight, turn key on
and I get 62psi pressure (in spec). Turn key off and it holds 25psi
pressure (there is no spec that I know of for this).
While running it never drops below 50psi (in spec) even when it is
acting up. While it is acting up and I accelerate the needle will
sweep between 50psi to 70psi very fast.
What concerns me is that after it is acting up and I turn the key off
the fuel pressure instantly DROPS to 0psi. It this an issue?
If I let the van sit for two minutes and turn the key on (pump on) then
back off again it will still drop to 0psi. If I let it sit overnight
it will again hold 25psi of pressure with the key off.

Codes
The check engine light (service engine soon) does work, but does NOT
turn on. I do not get any codes. To verify I rented an "Actron
Super AutoScanner" and checked the codes. I do not get any.

I know I can monitor real time data with this device (scanner) but I do
not know what to look for (suggestions?).



Do you guys have any suggestions on what to try next? I am about out
of ideas and I am thinking about taking it to the shop. If/when I take
it in, do you have and advice on what type of shop or diagnostic test I
should ask them to run (or not to run)?