when engine and weather is below freezing engine runs smooth at start up but shakes alot when put in gear. shaking goes away(not entirely) after car warm up and has been driven a few miles. plugs, wires, coils, coil plug wires and MAS (20,000 miles ago) have been changed. Shaking most pronounced with foot on break and in gear. i have put car in drive and with foot on break reved engine and gotten lots of engine vibration. aafter putting car up on lift checked motor mounts but saw no leaks, could they still be the problem or has my MAS gone bad again. i get no check engine warning like the last time it (MAS)failed. thanks joe d

 

check your tps some times this sensor givies this type of problems (olso call throtle body)

 

I had someone rev the engine with car in gear (drive) and noticed about an inch or two of enginelean to the drivers side. when in reverse and repeating process there was almost no lean at all.Can passenger side motor mount be bad?

 

try checking your Mercedes motor mount. It might need some replacement.