I've noticed that my A/F gauge is not reading correctly. My Power FC is saying that I'm running @ .85v @ WOT. However my A/F gauge is only lighting up the orange LEDs. According to the booklet that came with the Autometer gauge, the green LEDs should light up starting at .75v. So, when I go to WOT I should see at least two green LEDs light up. Whats going on with the gauge?

 

The voltage slope on OEM O2 sensors is so steep on either side of stoich that they are little more than on-off switches. Expecting any meter you connect to it to be "calibrated" blindly to the slope is a crap shoot. Different brands will have slighty different slopes and response times. Evey within one brand you will have tolerance issues.
I use my J&S gauge on the OEM sensor just to see if things are basically working or in closed loop. I use a wideband for meaningful data.

Of course this topic has been a beaten dead horse that a search would have yielded a conclusion to approximately the same results as above.