I'm not a technician so I can't really offer any meaningful advice, but I guess it would be awfully hard for a technician to reply because you haven't described how the car is running bad. I also sugget posting the year of your car because there were many changes over the years, such as catalytic converter (early 450 SL's had none, 74-75's have it in the engine compartment, and 76-80 have it in the usual position); later models had a different fuel injection system, etc.

Good luck.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".