Well I have not gotten back to the O2 sensor much past the initial troubleshooting but I did have an additional question.  In my measurements, once the engine gets hot, it seems that the sensor output goes to zero when disconnected from the controller (computer).  Is there a point in the thermal curve where the O2 sensor output does this before actively outputting a voltage?  Will the O2 sensor get hot enough with the engine running at idle or to I have to take it up to 2500-3000 RPM to get enough heat to make the sensor work?

I have another sensor (new) to try but wanted to find out more about the actual sensor operation first.

William