Car runs 30 secs then stubles and dies like the fuel is cut off or pinched off.

My question is, what happens in the ignition system after a cold start after 30+- secs that could cause the car to look at a sensor, that could be feeding bad info that it is not identifying at the initial cold start.

I've been through my Volvo official manual, looked athe computer, no codes
Changed out with known good part (off running 91 w/ same ignition), ECU (main computer), both fuel pumps, Idle air control valve, radio supression relay, fuel pump relay, I get a spark pulse to the dying revolution.

Does the ECU take into account a signal from the AMM or O2 sensor after a certain time???

The car will not restart after a stall, I can turn the ignition switch several times, then it will restart. I thought fuel, and swapped out the main fuel pump, filled the tank to the tip top, the intank pump was already replaced as I swapped out the sending unit (rusted out).

Tonight I will put a fuel gague on, it is a deal as there is no test port, and the rail connection is stuck, as in the rail will twist up prior to letting go. I'm going to move fuel pressure regulator off, splice in a guage with rubber hose and a tee. I had replaced the fuel pressure regulator with my old on removed for preventative maintenance a year ago with no change.

UUUGGGGHHHHHHH.

Any thoughts appreciated

I wil likely swap AMM and supply hoses with my running car on Sat also as a shot in the dark.