c class2011

Hello, I have a 2011 Mercedes c300 gas with 115k miles And lately when I start it in the morning or when I start of after the car has been sitting for a couple of days it has smelly dark grey-ish smoke I wonder if there’s anything wrong??? Thanks in advance

Hi I've recently just bought a used c220 from mercedes and in the last 2 weeks randomly when I am stopped in traffic with the brake on or with 'hold' on the whole car judders/wobbles??? I've read about just steering column juddering but this is the whole car!! Feels like it would be noticeable...