IT IS POSSIBLE THAT THE CAT IS PARTIALLY BLOCKED.i HAVE A CAR IN THE SHOP DOING THE EXACT SAME COMPLAINT,I'L LET YOU KNOW WHAT IT IS WHEN WE FIX IT.

Start by replacing the spark plugs, MB/Bosch suggest a MAXIMUN life of 5 years OR 100K which ever comes FIRST!

OR you could switch a coil & spark plug wires from a different cylinder & see if the problem moves to that cylinder!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator