I also have a 1988 300SEL (with 156k miles). Mine has never stalled until today. I pulled into a drive-thru for lunch and was waiting my turn. I had been stopped for like 20 seconds, car was running smooth and I looked down and the warning lights were on, the car had simply and smoothly stalled. I didnt even notice it had stalled until I saw the warning lights on where the engine had stopped. It started right back again, ran smoothly and never stalled again, but I am wondering if this is a sign of future and more often stalling to come?

Like I really need another problem... my Lexus is already doing enough of that (overdue for costly maintainence - valve cover gaskets, mounts and now the PS pump is leaking on the Lexus), I dont need the Mercedes to start causing problems too.

I had a stalling issue on my old W126 ('85 380SE) and turns out it was leaking injectors. I sold that car though.