In my experience when fuel pumps quit you get to call your favorite tow service. Does the tach drop like shuting off the key or does it follow rpm while the engine slows? I suspect ignition shutdown, probably electronic not mechanical. What I mean by that is it is most likely an ignition or computer issue not a relay or a fuse. The quick off and on is classic electronic failure.
Ford thick film ignition systems fail hot, they usually restart when cooled off. Of course my motorhome has this ignition system, but it has a huge factory heat sink.

It seems to fall with engine rpm vs key off drop to zero behavior

Indeed the few times it has absolutely stalled, it would not start for about 5 minutes. Once it did start, and back moving on the road, back into the same behavioral pattern.

One of the stalls was at the curb, idling for about 10 minutes w nephew listening to tunes killing time. This car heats up very quickly but the fan always catches it etc. However, the fan is not blowing on the ICM so I can see it getting pretty darn hot under there. Took 5 min to restart.

I will go dig through my cache of parts and see what I can not have to buy to troubleshoot.

Thanks

Believe me I'll keep you all posted

Good information about the tach. The fact that it drops with rpm indicates that the car is still in the run mode. The problem is likely downstream of the ignition command. So the ignition/ fuel is in the run mode and the ignition is failing.

Derf, Oh Well.

wtf?

Mega apologies for not updating this post.

After FINALLY getting under the hood, I swapped out both the ignition module (ICM) and the relays because I know they were good when I pulled them (all three) as part of troubleshooting some years ago.

So in went the original ICM and coils.

He is currently driving it locally.

Not a blip since.

My nephew is a bit shy to drive it, but I will take it out on a 100 mi cruise on the highway to prove to him that he has nothing to worry about.

Thanks again to all for putting your heads together and steering me towards the solution with sound reasoning.

That's why I love this forum.

Everyone chips in what they can when they can, and the result more often than not is a repaired or even resurrected Satty.