My ’93 945T has been giving me a 121 code on socket #2, Bosch fuel injection fault code, which is identified as:

Condition: Faulty signal to/from Air Mass Meter
Cause: Wiring fault to or in AMM

I cleard the code, it came back within 4 miles or so.

In the FAQ it states “The classic test of AMM failure is to disconnect it; if the car runs better, then the AMM is at fault.”

I went out and unplugged what I thought was the AMM and could tell no engine in how the engine ran, though I didn’t actually drive the car. I just left it in park and revved it up to ~ 3,000 to 3,500 rpms.

My question is this: did I actually unplug the AMM? The piece I unplugged is this black plastic box on the back side (facing the rear of the car) of the throttle body, opposite of the throttle linkage. As near as I can tell, this is the only sensor on the throttle body. Was this the AMM? Should I unplug it again and drive it for five miles or so?