1992 Mercedes Benz 300ce Black exhausst smoke

Engine Mechanical problem
1992 Mercedes Benz 300ce 6 cyl Two Wheel Drive Automatic 106000 miles

I just bought this car 2 weeks ago. I drove it to Atllanta from Florida and it drove fine, but kept noticing black smoke from the exhaust from the tailpipe. I put a Chevron additive into the tank and since it has been sputtering and hard starting. What would appear to be the problem? Is is the type of gasoline that was being put in?

Hi there,

Thank you for the donation,

Black smoke is a sign of a very rich mixture, start with pulling the plugs and looking for a black wet or sooty spark plug, this will indicate a miss firing cylinder that may be the problem, star there.

Mark (mhpautos)