I checked the O2 sensor from the connector under the hood using my multimeter. When I unplugged the connector and measured directly between the sensor wire and ground, the values went approxamately from .840 to .900( I think this is normal). However with the sensor wire connected properly to the car meter would briefly flash the above values and then change to some completely strange numbers, and then back to the correct values, and then back to strange values...... What gives? One of my manuals says to measure it the second way. Also the check engine light did not come on when the sensor was disconnected.

Thanks for your thoughts.