2011 c300 4matic has constant surging. Not bad at hiway speeds. really feel it at 40mph. -has to be under 4k rpm- Feels to me like an air leak. She has no codes, been to the dealer. Cost me 200$ an 4 hours for them to give up. said might be transmission. '-trash- since it happens in neu and idle...
Iv replacd the plugs. They all had a clean burn. i think i hear a leak near the drivers side valve cover but the PSpump is also noisy. bad Map? Could it be a fuel issue? O2?
shes has 170k miles, all factry parts, im the third owner.
all ideas welcome

 

I think you should go to the company to check the information of the car. may find an error. sure you have to check it regularly to see if there is anything out of the ordinary?

 

Everthing checks out. i did notice that there is a small leak in the evap sys. but its still with in the factory spec's

 

Your issue is solved? Please let me know soon because I am also facing this issue and can't find my question-answer anywhere. Even I have found your post while searching for the best business plans online and I came here in hope that I will find my problem solution but it makes me sad.