delorut,
P0100 refers to the MAF circuit not necessarily the MAF itself, could be some thing as simple as a bad connection in the plug.
I've been doing a lot of research myself trying to track down a P0171 code, learning a lot as I go. Something as simple as a bad seal around the O-ring on the oil dipstick can set off a code !


list of codes from MB.org...
http://www.benzworld.org/forums/gene...codes-dtc.html

OBD code's / trouble shooting...
http://www.obd-codes.com/p0100

P.S. over on the MB forum there suggesting not buying an after market MAF sensor but rather to be sure it's a genuine Bosch replacement.