It sounds to me like a symptom of a bad engine wiring harness.
They were bad on all MB's with the M104 engine from 93-95.
Do you know if yours has been replaced?
Do a search on engine wiring harness, and you'll be up all night reading.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".