When was the last time you changed the air filter, fuel filter, spark plugs? I'd try the basic stuff like that first. Maybe you could run some redline injector cleaner through your tank if you don't get results. A clogged cat converter may cause lack of power too. Good luck.
1994 C 280 117.5k, White (Good as new)
1997 Toyota Camry 149k Miles (Not so pretty anymore)
1990 190e 2.6 95k (Sold-Should not have)
1981 240d Stick ??? Miles...sold