naw thats normal. if you revved higher it would have made more smoke. do a few performance bursts and it will get most of it out of the system. MBs have such restrictive cats that it won't produce nearly as much smoke as say on an afteramarket high flow cat or etc. You did everything the right way. I always run a full can of seafoam on only a half tank of gas (very concentrated dose) and it usually does wonder, gets rid of all hesitation and etc. now enjoy