So, I've a 92 Accord EX Sedan Auto, 216k and counting. Over the past month, 3 times it randomly died out while driving down the road. All these times it happened after I turned the car off, ran in somewhere quick and came back out to leave (less than 5 minutes off). Yesterday, it died out 5 times in the span of 2 blocks without an engine shutoff, and I barely limped it home to my house. Today, it died twice in Park in my driveway. Idle isn't sputtering, no miss, just dies out flat, whether in Park at idle, or in D4 moving under load. I've searched quite a bit, but could use some fresh input as some threads are dead/invalid on numerous forums and this one.

What I do know:

Seems to die out when engine gets up to operating temperature.
I'm (somewhat) ruling out the main relay, as I swapped in an RZ-0132 from a Civic I parted (Accord OEM is RZ-0088), and the problem still occurred.
CEL STAYS ON after key has been turned to the on position, fuel pump primes.
Only other code I'm throwing is Code 12 (EGR Valve), which has been going bad for quite a while.
I have an ICM in the mail on the way.
ECU (green/yellow) wire appears to have a good connection.
Cleaned all under hood grounds.

What I don't know:

Fuel pump primes, but could it die out while driving or parked?
Has my coil or ICM gone bad perhaps?
Has my ECU gone bad?
?????

Any help is greatly appreciated, I intend to run an ohmmeter when I can, but it's a little cold here in the Midwest at the moment.