Thank you for bumping a 3 year old thread with an answer that has already been givenYou connect the O2 sensor OUTPUT wire to the you INPUT on your AFR gauge. And the gauge SHOULD fluctuate. Thats because in order to maintain proper afr's your O2 switches rich lean rich lean to maintain a stoic reading. yes i know this thread is old. Trying to help. And there worthless for BOOSTED application however for your stock setup it mimics exactly as your ecu sees it. because both your stock O2 and your afr gauge are slow.