My 2011 c300 has 87k miles and for the past 2k has been sluggish until it's really warm. The best way I can describe what's happening with acceleration is it feels like it's congested. Like when you're trying to breathe with a bad cold. When the car is warmed up it accelerates with the smooth sound and feel as when I bought it. But when it's still cold, it feels like your throat and lungs when they dealing with a lot of phlegm.

Is this possibly dirty sensors for fuel injection? Or is could it be more of a problem in the engine? Is there such thing as a tune up that can be performed for this year/make/model that I might be in need of? I'm willing to do what I have to to make this car last for into the 110k mark. I would love to keep it's performance good.

And aside from that, the service at the dealer a couple services back told me I might wanna consider getting the motor-mounts replaced around 80k or 85k. Is that sound advice? He said that based on the position of the engine at 75k (when he gave this advice) that I should replace them.

Thanks for looking at my question! any help would be super appreciated.