One more thing - does your cruise control work?
Another symptom of a bad throttle actuator is a mal-functioning cruise control.
Our wonderful German engineers designed 3 or 4 separate functions into the actuator. If any of these go out, you're replacing a $1,000 part.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".