Purchased a used '03 C240 2 years ago. Ran fine, about 8 months in began to tremble when at rest/idling- both with and without brake on. To a non-knowledgeable me, feels as though something is misfiring...but what do I know?!
Took to Mercedes dealer, they couldn't identify a cause to fix but did other maintenance work ($1500). I brought it back to them again 2 weeks later, as shaking seemed to be worse (you could see car was shaking from outside te car), and now occasionally the check engine light would come on intermittently...sometimes just for 10 mins, sometimes longer. Left it with them again for several days, again they said they couldn't find anything definitive to cause the shaking at idle, but thought it worth trying to so several other things like replace engine mount, change hoses, whatever. No difference. I don't doubt that they did work both times, but from my perspective I was without my car and out of pocket and still having the same issue afterward that brought me in in the first place.
I figure of all people to know what is wrong, Mercedes dealer should...and have been reluctant to take elsewhere for additional opinions due to cashflow and worry someone may mess things up further.
Fortunately, I drive this car very little so mileage on whatever's going on with it is fairly limited...although still shaking, the check engine light had stopped going on as often.
Fast forward a year...took to a garage recommended to me for oil change, they also said I needed other work done...coils, plugs? I'll have to look back at receipt- my husband had taken it in.
Ran same as usual initially afterward...now a week later my check engine light has been coming on again, and now in addition to the trembling, I have been noticing VERY slow acceleration...I'm putting my foot to the floor when pulling out of parking lots into regular city traffic, etc.
Can anyone help??? Similar experiences? What I should look into??? How on earth can the dealer not tell something is wrong with the car or know what to do to fix it??