how sensitive are the O2 sensors in our cars,

you may ask, why does he want to know that ???

well, I recently installed the home made mixture gauge listed elsewhere on this site, it is the wideband version and very sensitive to the voltage changes from the O2 sensor. my problem is that this thing dances all over the place, from ideal mixture to very lean and back again in the course of a second or so. some times it stays very steady at ideal mixture and others it dances.

is the sensor that sensitive to mixture changes or is my O2 sensor taking a dump on me ????

P.S. I know all my connections are good.

 

On our computer at work the O2 voltage jumps all over the place on most cars, including mine....so I would say that its normal but thats just my .02

 

Are you saying you have the "indicator" wired directly into the OEM O2 sensor? If so, then yes that is normal.

The O2 sensors used in just about every car are called switching type O2 sensors. The voltage will jump up and down. Depending how far and how often the voltage crosses .450 mV is how the ECM determines the AFR. IMO, the "10 LED" indicator that you plug into the OEM O2 sensor is good for nothing but finding out if the sensor is heating up enough, and estimating when the ECM is going into closed loop. It IS NOT good for determing AFR at WOT.

A wideband O2 sensor is something TOTALLY different.