I have purchased a 2014 MCS F56 a few weeks ago. When driving in stop and go traffic the idle would race up to 1500 RPM and eventually set the check engine light. I cleared it a few times and the problem went away until I was stuck in stop and go traffic again. When it did this the start stop feature would not work. My mechanic smoked the evap system and found no leaks. We did some research and found out this combination some times is caused by the Evap control valve on the front of the engine atop the intake manifold. Upon checking it did seam stuck open. Replacing this valve corrected the problem and was easy to repair.

 

Good reference info! Thanks - how many miles on the car?

 

105000

 

Had the same problem happen to me but I was around 66k. After changing the same part I did use CRC 1 Tank which all seemed to help.