Howdy,
91 740 Turbo has fault codes for lean mixture: 221, 113 and 231.
Vacuum leak ruled out by smoke test.
Car starts but cannot maintain an idle without stalling, and RPMs fluctuate wildly even with steady throttle positioning.
It runs almost normal with the air mass meter disconnected, BUT the fine wire filaments in the sensor portion appear to be intact and the wiring harness appears well connected.

My attempts to follow the Chilton guide for multimeter testing were foiled because they referenced an AMM(unknown model or year) with 3 connections plus ground and no wire colour references for which were the "signal return" or "signal circuit" wires. Also, the connector on my AMM has 4 wires plus ground! Therefore, confirming the voltage specs with Chilton was impossible.

Suggestions??