Car stalling AGAIN, Updates- none of them good. Options

[rjames]

Drove around for 30 minutes in 80+ degree weather. All arterial roads, so several stop lights, etc. No problems until I was almost home. Car stalled when I stopped at a light. RPMs just dropped to zero. Was able to start it again with a little difficulty and had to keep my foot on the gas to keep it from stalling out again. Power seemed ok though the rest of the way home (I think). It stalled once again at a stop light a couple of blocks from home and then again when I pulled in the driveway. I let it sit for 30 seconds, started it again and it idled just fine. Rock solid at 1000 RPMs. Pulled it into the garage where it sits now.

Prior to today the car has been running and idling perfectly since I went through the FI parts last year, which included installing a 123 distributor, new CHT sensor, a newly rebuilt mps (calibrated for correct afr on my engine), new vacuum hoses, NOS throttle body, rebuilt injectors, new fuel pump, valve adjustment and timing.

I haven’t checked the AFR since last year, not sure why it would change though.
It’s a ‘75 so the fuel pump is in the front, so I can rule out vapor lock I think.

Anyone have ideas as to why it would be stalling?

[rjames]

It’s back. Was running fine with no issues for several long outings. Then yesterday it started happening again after 20 minutes of driving. Verified the fuel pump is working.
Power seems fine above 2000rpm. If I press in the clutch and let off the gas the RPMs drop to zero and car dies.
When it’s in this state, in neutral the car does not rev smoothly when below 2000rpms and is hard to keep running. If in gear and driving, I can keep the car running without any real issue as long as I’m giving it gas.

Each time after it dies it starts right up no problems, but I do have to keep the rpms up to keep it running.
Something else I noticed was the rpms kind of jumping erratically up 100 rpms while maintaining a constant speed on the freeway. Hadn’t seen that before.

Given everything I’ve already tried to solve this, I’m starting to suspect the 123 distributor. I have the stock distributor I can swap back in but really hate having to go through all that again.
Symptoms don't seem indicative of a bad distributor based on what I've read on the interwebs. Anyone think this could be a distributor issue?

If the compression was bad, that would mean it would be doing this all the time instead of intermittently, right?