1991 300 SL stalling/restarting

[Shaggydog199]

My 1991 300 SL (52000 miles)will periodically stall when comming to a stop. Both the idle control valve and oxygen sensor have been replaced and the fuel mixture was made richer. It still does it! Only happens periodocally and usually when stopping after acceleration. The real problem is it won't retart for about three minutes. Then things seem fine. If I keep the RPM's up by applying slight pressure to the gas pedal while stopping it will not stall. I'd like to give my crack mechanic some advise so he doesn't continue to guess!

Any ideas on the cause and the reason why it will not start for awhile. Very embarassing to be sitting at a busy intersection in a beautifull Benz with the emergency blinkers on!