Finally found problem!
Back on November 13, I posted a question about my 89 300SE that would start and immediately die.
Every time it was towed to the shop, it ran perfectly for the "Doctor." On a cold night right after Christmas, it had run for an hour and half (long commutes in Atlanta) and then died, caput...now for the third tow!!!
Problem was a faulty fuel pump relay....the dead one was made in Austria...the replacement was made in Germany.
So at last a solution to the dying problem.
Many thanks to all who offered suggestions.