Ignition Control Module problem

I don't see where the OP fixed this. I just re-read and the fact that 2 ECU boxes both quit sparking ~2000 rpm suggests the pickup in the distributor might be the culprit. Check the gap to the reluctor teeth (preferably brass feeler gage). I recall 8 mil, but the closer the better as long as the teeth don't hit. Also, check that the rotor shaft is solid and can't wobble sideways.