My 06 slk 55 just had its service D five days ago (just cleared 40k). Yesterday, coming back from a long road trip, while I was driving, the check engine light goes on. And then when I come to a stop (in drive, foot on brake) the car starts to vibrates, moving back and forth. Like a person shivering when it's cold. I noticed the rpm gauge starts to jump up and down a bit, as if gas was being applied. The shaking stops when I let go of the brake and ease the car forward. It had happened several times since yesterday. Nothing else changed, still accelerates and shifts normally while driving.

I'm taking it in the dealer first thing monday morning, but does anybody have any idea what this maybe?

 

Idle adjustment - they need to raise your RPM level at Idle so your ECU isn't chasing, what it percieves, as an imminent engine stall. Your engine is fine, your ECU just needs calibration (which they should do for free since the car was just there).

 

UPDATE:
It turned out to be a faulty ait flow sensor. had it replaced.
They also replaced two valve gasket covers since they were leaking oil.
All under warranty. Glad to have my baby back!