Still trying to troubleshoot this problem.I have the service CD and the test proceedure but I don't have the harnness or the socket box tester.I THINK it's the throttle actuator but would like to confirm before spending the$$$$. I've had this problem for over a year and initially replaced the throttle pot at the suggestion of a local MB tech. They said if this doesnt fix it that it's probably the actuator.Any help would be really appreciated...thanks,Dan