CLK Rough Idle
if it shakes in gear w/ your foot on the brake then u have a problem, even if the shakes is very small.
the most likely culprit is one or more spark plug wire(s) going bad. if you have some miles on your car i would recomend replacing them all. 16 for a v8 and 12 for a v6.
the other possibility are blown motor mounts or trans mounts but highly unlikely.
not a tech or anything just talking from exprience. had the same problem, took it to the dealer, they diag it as the no. 6 wire and replaced it and it went away. after a year and 1/2 the problem came back, just replaced all my wires myself and the shaking went away.



