recently changed my spark plugs on my 2011 C300, after changing them everything ran fine for about two days. Now when I start the engine the car revs uncontrollably from regular idle to about 2000rpm and then back down and back up again. It does this until the engine warms up and then continues to run fine. Anyone know what could be causing this?

 

Sounds like a pedal position or throttle body sensor-----why guess get the car diagnosed!!

 

Well... lets see here. 1. your in the wrong forum this is for c class cars up to 07. 2. have you done any investigating, got any codes read?

 

Moved to w204