I will leave the stalling issue to Benzmac and MB DOC but the 90-100 C temp in traffic, especially A/C+traffic, is normal. It should come back down once you get moving(hence airflow) or the electric fans kick on. If it stays up around 100 C once you are moving for awhile (cruising down highway at speedlimit+) then I would have it checked out. Sorry I can't help too much with the stalling issue. That is for Benzmac or the DOC. You wouldn't by any chance know the malfunction codes from the engine warning light or lights?