Start with the obvious. Low power suggests a fuel system related issue.
The MAF is responsible for 90% of fuel system input.
USE only a Bosch complete air mass sensor!
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
42 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)