Hello Rick:

Get a cheap digital multimeter ($5 at Harbor Freight). Set the scale to 1V DC. Warm the car up well (normal operating temp). Then touch the spade connector on that green wire you describe with the red probe and touch the black one to a good ground underhood. If the sensor is good, you will see a fluctuation from .1 to .9V with a cycle something like once per second. If it stays pegged at either extreme, you have a problem. As they age they get lazy too-- sometimes the range will shrink quite a bit-- replacement is in order then too, but you probably aren't running so rich as to do your catalytic converter in. Given gas prices these days a new sensor will pay for itself pretty quickly, though...

Does the car have symptoms? Reduced mileage, black tailpipe, running hot?

Good luck!



--
Herb Goltz, London, Ontario, Canada '92 245 w/109K mi