Here's one for you. Last night I removed our O2 = sensor and did a little test. I brought it inside, connected it to a digital = mult-meter and heated it (gently) over an electric stove. At first the meter read 0.00, within about 15 seconds it started bouncing around between = 0.17 and -0.17. I realize that without an exhaust stream these values are irrelevant. What was amazing was that I got these readings without = the black lead on the meter connected to anything. The signal wire on = the O2 sensor was connected to the red lead. The wire is not coaxial so there = is no ground confusion here. When I touched the black lead of the meter = to the O2 body or threads it made no difference in readings. I = consistently read an output from the sensor with the black lead of the meter hanging in = mid air! Are these sensors magic or was my stupid test creating static = voltage or a "force field" or something? Try it!