There's some replacement AMMs for RWD that use a thermistor
instead of a heated platinum wire.
A review at Swedish auto parts says its a good substitute.
The review indicates that a messed up AMM can cause the engine to run rich.
My car runs rich with black soot around the new stainless exhaust pipe and ratty gas mileage.
I just replaced the old O2 sensor and wonder about my old AMM.

Another site that rehabs old AMM's says that they calibrate them perhaps using
a trim pot in the AMM.

I have a pair of old AMM's with the 4 small steel phillips head screws for the cover solidly frozen into metal casting.
Months soak with penetrating oil doesn't work, and you can't put heat because the cover is plastic. Can these be re-calibrated? Then I can drill out the screws and have at it and jury rig the cover back on.
I can't find any info other than some resistance values at the connector.

Does anyone have info on the circuit board hidden under that cover, and info to
adjust the AMM. Or is it a waste of time, and better to buy a thermistor AMM?

Thanks, Bill