Monitor things while driving. Do whatever it takes to set up testing gauges to see what is going on.

Start with a fuel pressure gauge. Rig one up it is sticking out from under the hood so you can see it while driving.

And a multimeter wired to the spark control module +12 volts and ground. See if it is losing power.

When the car stalls next time, look at your testing gauges - see where the trouble is.