I do know the pump is getting full voltage, consistently. Tested at the terminals with the car running and with the AFM flap jammed open, key to accessory.
What I've noticed is that from a cold start, fuel pressure might max around 28 psi, then drop to about 21 or 22 before the car stalls. But it'll hold there indefinitely. It's been three days and it's still at 21 psi (again, I'm extremely happy to know I have no injector or hose leaks). But when I restart after a stall, slightly warm, the pressure will actually jump up to 35-ish and it'll run fine for a bit before it begins to dwindle. Sometimes that dwindling happens within seconds, sometimes it takes MANY minutes. It's not consistent, although it does seem that more often lately it'll begin to die fairly quickly, whereas weeks ago it would take much longer or maybe not at all.
Opening the throttle slowly but consistently, revving from idle to about 3500 rpm, the pressure will hold where it was, but not necessarily rise. As soon as I release there's an immediate drop and stumble. Sometimes it'll recover a bit, but often it'll immediately begin to stall. It does not like throttle snaps AT ALL. Immediate choking.
The inertia switch is bypassed. I did rebuild it a few years ago, but realized the copper contacts need to be de-oxidized about every six months, the springs for the ball bearing re-tensioned, the connectors cleaned... it's just too finicky. The pink wires are now butt spliced.
No fuel present in the clear vacuum line. I'm really leaning toward the fuel pump. That new fuel pump. That highly suspect $50 eBay fuel pump...
as good as a car can be... briefly.