Throw your lightshow autometer guage into the garbage or sell it because it wont really tell you anything.

The big fat white wire in your engine harness under the pass side kick panel is the source for 02 readings.

I believe since your running an ecu that uses 1 02 sensor you have to tap directly into the 02 sensor area of your harness to get an accurate voltage output reading to your autometer guage.

Regardless autometer guages don't tell you anything that a voltmeter wouldnt tell you