If it were my car at this point I would run two bottles of Techron Fuel Injector cleaner through it with less than a full tank of fuel. I would get hot and drive it hard, say in the hills.
If that didn't clear it up I would bleed the fuel injector lines at the fuel distributor. A dangerous job >raw fuel on a running engine< but often on older cars seems to help.
I did the above on the 190E which ran so poorly I was sure it had severe internal problems. When I bled the injector lines I was amazed at the amount of crud that came out. I did it several times.
The 190E now runs very well, lots of power and almost a perfect idle.
Keep us posted,
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)