I have a 1994 SL500 with a ASR light. Sporadically my ASR light comes on and my engine shuts down to idle speed when driving on the road and/or at speeds of 20-40 MPH. At that point I have to shut the engine off and restart the car. At that time my car runs normal again. I have been told that it is most likely because of my Throttle Body Actuator. The problem doesn't happen all the time. In fact, it only seems to happen wehn it is hot outside (70 degrees and above). You can buy rebuilt Throttle Body Accuators for between $399-$799.00. One such place it Jayten on the internet. Their site is: http://www.jaytanindustriesinc.com/index.htm.
Thanks, Rgrayoh