I put an ohm meter on the Air Flow Sensor on a 300E.
I get inconsistent readouts, and jumpy readings. I am
assuming there is crud on the wipers of the potentiometer
inside. I would like to replace it, but cannot find one
at any parts houses. all they sell are Air Flow Meters,
which in the books, point to the intake housing that the
fuel distributor mounts on.

The car looses power AFTER a quick stop. Then it seems to
run 'rich', for a mile or so, then "jumps" to full power.
(Disconnecting the ESH solves the problem, but then I have
no cold-start ability.) An eratic Air Flow Sensor seems
logical to this problem. True? Or other sensor? (The
computer has been replaced, and did not solve the problem.)
The only thing that abated the problem ws to spray "Gummout"
in the Air Flow Meter throat/hinge area (near the A/F Sens.)

Any place I can locate a "Sensor".??? Or repair the one
I have???

To get a new sensor you MUST purchase the shiny aluminum housing that it's bolted to. Thank UNCLE Sam for that! Very hard to calibrate w/o dyno, so spend $500-$600 & you get new sensor. Part number is 000-074-20-14 & has $585. list

is it that whole assembly underneath the
air filter housing??

Yes, the Air Flow Meter is the large (5x10") cast aluminum
intake housing that the fuel distributor sits on, under
the BIG air filter housing.