Pull the spark plugs, they can give you an immediate read on too much oil going into the combustion chamber.
Also, look carefully on the right side of the engine, front, where the head meets the block, just a little bit below the distributor cap. A typical leak point is the upper cover seal. Our 91 300E with 212k miles was using quite a bit of oil. I did this repair and after almost 3k miles, I am still waiting to see when I will need to add oil again.
You can also try using one of the "High Mileage" oils, such as Valvoline MaxLife. They do *condition* older seals. They don't end problems but these oils do help.
You need to adjust your bowden cable.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)