That sounds familiar from my 560sel, but i can't visualize what i was working on and thought solved it--cold start valve?? Cylindrical thing in front of the air cleaner housing if i recall correctly. Might not have been it at all...sorry.

But...in the fall/winter in all our vehicles over the past several years, we've dropped performance and fuel economy. I've heard rumors of "winter formulation" gasoline, perhaps with a touch of alcohol, but have not been able to verify that. I can say that in the winter months if i put a bottle of Techron in a fill-up it makes my car run like it's spring-time.

Good luck!!

__________________
Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)