Pete:

Your 02 sensor measurements might not be a problem-- whatever multimeter you use it MUST be a high impedance device (say 20M ohm) to give an accurate reading. Many analog meters aren't high impedance, which would cause the discrepancies in your measurements...

With the car warm and at idle, you should measure voltages between 0.1-0.9VDC, fluctuating at around 1Hz (once per second).

Good luck!

Herb Goltz, London, Ontario, Canada '89 760GLE w/170K mi