If it starts fine when cold but just won't accel properly, I would think that you have a vacuum line to the warm up regulator off. To test requires the use of a special fuel pressure gauge set up.

------------------
Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM