Fuel Fuel Issue

I've been chasing an intermittent issue for the better part of the last two months or so, and thanks to some reading here, I have the issue narrowed down to (I hope) one of possibly two things. Periodically, my 87 5.0 will sputter and die, and then not restart. It's seems to be fuel-related, as I have spark going to all of the plugs, the plugs/wires/cap are all new, as are the ignition coil, starter solenoid, and ignition module. The throttle body is clean, and I have the Throttle Position Sensor set to the proper voltage. The fuel filter and the fuel relay are relatively new (about a year), and the inertia switch is operating properly. So at this point, I'm thinking that it's either the fuel pump or the fuel pressure regulator. When I put a pressure gauge onto the Schrader Valve, I get about 32 PSI when the car is running, but when I disconnect the vacuum line on the regulator, the pressure jumps up to about 42 PSI. No fuel escapes when I pull the vacuum line, and there's no vacuum leak since I can feel it pull a vacuum on my finger when I cover the end of the line. Any thoughts and insight would be immensely appreciated.

The only code I get is 33 with the engine running. I get 11 with the engine off and no codes when I do the cylinder balance test. It will run with the spout connector plugged in.

I tried the spout plug the last time it did it, and it still wouldn’t start. When it happens, the engine tries to turn over, but doesn’t - it’s behaves like when you run out of gas and try to start the car, that’s why I was thinking it was fuel-related. There’s spark going to the plugs when you try to start, as well.

I replaced the TFI about a year ago with a Motorcraft replacement part, so I would assume that it’s good. EGR is still present, although I replaced it about two years ago with a non-Motorcraft part, so maybe I got burned on that? The car is stock, no mods. I assume that the pump is stock, and possibly the original, although I did find a crap ton of zip ties in the general area of the tank. I checked them and none of the hoses appear pinched by a tie that’s too tight.