While you are in there with the air filter - make sure that the foam insulation isn't falling off and clogging the air flow sensor.

On my 190E 2.3 it really needed to get vacuumed out.

__________________
2004 E320 4matic
2000 E320 wagon
-- in the past---
1992 190E 2.3 5-speed! (European Delivery Baby)
2000 ML320
1978 240D - 340k mi