I have a 92 300SL, 89K miles that did the same thing. Cold start no problem, drive for a few miles, then it starts cutting out and trying to die. Even left me stranded one morning and had to tow to shop, where they found no problems! Solution was new distributor cap and rotor. I think they were the original equipment. The o-ring was dry and hard, and I think it was allowing moisture in, when the engine got warm, the moisture condensed, and it ran terrible until the moisture was gone. Runs perfect today. Try ********AZ for the parts as they were lowest price by far. Steve