HELP: 190E air-flow meter potentiometer worn...

[aander]

Hello all,

On both of my high mileage 190E-s 2.3 4V and
16V (both 1986) the potentiometer measuring
the air flow (on the side of the chamber just
below the air filter) is worn: reading are
very erratic.

Can someone tell me what the purpose of these
sensors is:

(1) Do they work to compensate for
air/fuel mixture when accelerator pedal is
suddenly depressed?

(2) Also, how much benefit in peformance/
driveability can I expect after spending
$600+ to replace the assembly. After serveral
inquiries I understand that the potentiometer
only is not available; one needs to buy the whole
housing and that is why it costs so much.

(3) Is there an after-market replacement for
the sensor only? Or, is there a shop that would
do it?

Any info greatly appreciated.
TIA,
Tony Ander
PS: Any sources in Germany??? I will be there for
a week later this month...