Rusty (off to test my O2 reading on the EM-2)  

 

Rusty, I tested a new mixture monitor (small 2" instrument) and found that bar 5 (first green bar) comes on at .546 v  which is what I would expect.  Bar 10 (second red bar at top) came on at 1.1V.  This sanity checks with what I found when I used this meter in that bar 10 would usually not light even at very rich mixtures.   The EM2 was calibrated to be full scale at about .950 V.

 

I'm stick'n to my story.  Full output on O2 sensors is 1 V.   Don't know where your problem is but this should point you in the right direction.

 

Tracy