I installed my autometer O2 gauge last night and when I tested it verses my scan tool the gauge appears to be reading STFT. It was my understanding that the 02 gauge was sort of a volt gauge reading the millivolts the 02 sensor puts out? Right? If this is true then why/how is the gauge reading matching my STFT?

P.S. my 02 volts are at .6xx during normal driving. I dont want to test nitrous until I better understand my STFT verses 02 Volts dilemma.

 

Your O2 gauge is slow. Normal driving you should see it swing across .450mV. Put a digital voltmeter on it.

Its impossible for it to read STFT, it'll be similar but STFT is a value that only exists in the software running on the pcm.