I am experiencing a noticeable vibration at 1,300RPM when the engine is cold and is not under a load. There are no misfires reported by the ME, and it is more noticeable before the engine has warmed up. When the car is in gear and under light acceleration, it is also apparent, however not nearly as much. Anyone have any experience with this? 24 new OEM spark plugs were also installed recently, and the vibration existed before and after the plug change.

Vehicle is a 221.176 S600.

Thank you

Sounds like it could be motor mount related? Usually vibrations coming from up front especially at lower RPM or when the AC compressor kicks on is motor mount related. Have you checked those?

Tranny mount most likely. But it could be the motor mounts. Just replace the tranny one and Inspect the motor ones for leaks.

Engine mounts are likely the cause as stated. Had this on our SL600 and did the tranny mounts and turbo seals at the same time as the engine had to come out.

I believe thats not needed on the W221.

Thanks guys. I was thinking it could be the harmonic balancer, but was hoping that was not the case, as I have not seen any indication this is common on the M275. I will certainly check the transmission and motor mounts.