Update on low/noisy idle and black smoke at idle....
 

It's a 98 CLK 320. I replaced all 12 plugs with OEM plugs and the low/noisy/rough idle went away but the black emmissions at idle is still there. Doesn't smell like gas...can't really say what it smells like. It doesn't smell like much. Any input on what it could be?

shameless bump....

black smoke?
 

dont know what else it could be except unburnt gas.

tom w