Oxygen sensors ~ interpreting readings
 

When driving and coasting in neutral, the bank 1 / 1 sensor fluctuates between low & high readings on the Ultragauge, whereas the bank 1 / 2 sensor goes to low readings and stays there.

Is this normal, or is the bank 1 / 1 sensor going bad?

Assuming "bank 2" is actually bank 1 sensor 2
If the gauge can only read out high or low, I'd call it normal

The gauge shows readings to 3 points, but they fluctuate quite a bit.

I will get samples and post them.

Assuming we are talking about the listed 99 Civic- Bank one would be the O2 sensor before the Catalytic converter, while bank 2 is after the Catalytic converter. The bank one sensor sees fluctuating oxygen levels and adjust fuel to match. Bank two is just checking the function of the Catalytic converter so it see very little change. If you are getting so much fluctuation that the ECU throws a warning light, there may be a crack in the manifold near the bank one O2 sensor.

This must be normal then. Thanks for the explanation.

Is there any way to tell from the Ultragauge if the sensors are functioning optimally?