For you new-comers to the list, I have a gadget available to monitor the
output of the O2 sensor. See my web site below. It is small enough to fit in
the switch blank below the emergency flasher switch.
   The display is a moving dot indicator that reflects the voltage output,
basically a dedicated zero to .9 volt indicator. From the behavior of the
moving dot you can tell several things about what the enigine is doing.
Rapid movement back and forth is normal, closed-loop operation. Release the
gas pedal, and if the idle position switch is functioning, the dot goes
rich (to the right) for a second then lean followed by slow oscillation at
idle.
   When you first start the car the dot floats in the middle. If it did not
then you know something is wrong.
  I could go on but you can read more on my website.
Good Luck and Drive safely,
Ken Lewis
http://neksiwel.20m.com/