a/f gauge not working. car possibly lean.
 

hey niggas. i installed my generic air fuel gauge a few days ago and it doesnt seem to work. i have it hooked into the ecu at the wire that goes to the o2 sensor, which is the right way to hook it up (or so i've heard.) when i am driving, the a/f gauge doesnt move, and is stuck in the red (sometimes one of the yellow bars goes on, but the meter barely moves) and i've seen countless a/f gauges and all of them bounce around when they are working correctly. i have the power hooked into the light for the cigarette lighter thing so the gauge is only on when i have the interior lights on. could that be affecting the gauge's functionality at all? one thing that worries me about all this is that it is stuck on lean and not on rich or somewhere in the middle. could my car possibly be running that lean? i dont hear any detonation when i hit 7 lbs of boost and i'm only getting about 220-250 miles per tank of gas... so i thought it would be rich instead of lean. i was thinking also that my 02 sensor could be going out, but that doesnt do anything at idle does it? this little problem has been bugging me for a while and i'd like to know whether my engine is REALLY running rich or lean so i would really appreciate some help guys. thanks -jacob

car is 87 T2 with 79k miles on mostly 15 year old parts.