Hot or cold start? Had a similar issue with my 190E 2.6, both cold and hot. Cranking speed was on the slow side, and I knew the battery was weak. It was a 17-year old Johnson Controls 26R that I had killed stone dead twice over the years. I finally replaced it (another Johnson Controls 26R from Walmart - only 50 bucks), and the problem went away. I figure low cranking voltage affected the cold start enhancements, which are in the "E" part of the KE system.

Prior to replacing the battery I always gave the throttle a little kick once it fired, and that usually kept it from stalling or running rough for the first few seconds, but the new battery with higher cranking voltage/speed was the answer.

Duke