I wish I could be more specific...
It does not seem right to me that when you let go of the gas (and driving) that the car almost stalls and then starts back up or stalls.... none of my other cars do that, granted none of them are Mercedes. In my 96 Ford Ranger it was a problem of the idle solenoid located on the throttle body.
So I will advance the timing to 10deg and see how it drives then. I will also try to spray carb cleaner around the manifold and the air intake to see if there is a possible leak.

Dmitri