Others know better than I, but I'll suggest this:

I had a 300E with the same symptoms. Try another fuel pump relay and the overvoltage protection relay.


Try another mechanic.

__________________
David

His:
2003 Dodge Durango SLT
2002 BMW E39 530i Sport
1988 Mercedes 300TE
Hers:
2003 Chevrolet Suburban
1999 E430