ok since nobody will post how to do this on a rear o2 i will

t tap the rear o2 White wire the gauge will not be accurate if you have a resistor fix, because this resistor limit the ability of the o2 to heat up i beleive it keeps it at a certain temperature that makes the ecu see a certain value. so in essense your af gauge will not read accurately .

i notice that on mine at full throttle it does read rich. and it will fluctiate back and forth but very slowly and generally only under extreme acceleration or when you just let off the throttle fast it will go fast into "lean" so basically if your at full throttle and it goes anywhere other than in green stop. lol its a light show i may go buy a single non heated o2 which will give me a more accurate reading BTW anyone know if that would make a difference?