Hi Guys, my pick-up starts fine and run for about 5 minutes. Then stalls from any rpm 5 to 10 times for about 10 minutes. Starts right up each time. Then seems to improve. Doesn't look like I'll be stranded for now but it'* a PITA. Get error code 54 (low fuel pump voltage) each time. Not really an intermittent problem because it happens every time the engine warms up. Fuel pump and distributor are fairly new with about 10K km'* on them. Changed the CTS and fuel pressure reg. but didn't help. Disconnected connection at oil pressure switch and engine continues to run fine via the pump relay. Disconnected the EGR and didn't change anything. Maybe ECM?

Welcome to the forums!
Have you tried a new fuel pump relay to see if that'* it...??

Also on a side note, have you changed fuel filter?

Thanks. No, not yet. I think I'll get a fuel pressure gauge setup first to see what'* going on with that when it quits. The fuel pressure regulator was just a kit without a new spring. I wonder if the spring is weak. Took my ECM apart just to see if anything obvious wrong on the circuit board but looks perfect. Oh, and it got a new Cat Converter and O2 sensor last summer. I also checked voltage at the 20 amp fuel pump fuse and it stayed at 14 volts while the engine quit. It'* the fuse on the firewall passenger side. Not sure where it is in the circuit from the pump or relay?

I think 11 psi is minimum 13 normal range...
Is your relay on the firewall?
Test info here.. Part 1 -1994 Fuel Pump Circuit Tests (GM 4.3L, 5.0L, 5.7L)

Thanks, I'll let you know what I get for pressure. Yes relay is near the fuse on firewall. It was easy to check voltage at the fuse but I think I need to poke into wires at the relay.

Update:
Replaced fuel filter. Still stalling.
Plumbed a 0-30 psi gauge into the filter and shows 11 psi while running. I squeezed the return line a bit with a vise grip and boosted the pressure to 14 psi. Still quit while pressure steady at 14 psi. So pump and its wiring/relay all good. Now wondering what'* next?

hmmm...That'* a tbi system ...
You got any bright, clear, engine bay shots with air cleaner off that you could post ?
I am going to call in one of our GearHeads & ask for further input...

Yes it'* got TBI fuel system.

Not sure if photo got attached. Here it is again. I'm thinking now maybe something on the distributor. It'* getting harder to start now when it stalls. Last time when I poured a bit of fuel into the throttle body it started right away then ran for about a minute before stalling again.

Removed the ICM. Possibly the problem. The heat sink grease was pretty much gone and one of the 2 mounting screws was loose. Does anyone know how to test these? Maybe it'* working until it gets too hot? Don't want to replace any more good parts to find a bad one.