Next time it does this, immediately pull the cover for the air filter and take a look in the airflow sensor. If it is full of ice, you are going to have to block the crankcase ventilation hose to the air filter housing until warm weather comes back, and put a filter of some sort on the hose itself to keep dirt out of the engine. Moisture collecting in the engine when run cold will evaporate when the engine warms up and collect on the air flow sensor venturi and cause the engine to go way rich and stall. Melts in a couple minutes when you stop, car runs fine, sometimes for the rest of the day.

Real cure is to eliminate the condesate -- either by driving only until the engine gets fully warm or by dealing with the blowby problems that cause excess water accumulation.

I had this problem with my Audi Fox 20 years ago.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!