Do you know if the engine wiring harness has been replaced? They are all bad on C280's and E320's from 1993-1995.
In addition to the engine wiring harness, I would suspect the Mass Air Meter or the throttle actuator.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".