Going back a bit here...

At 08:18 PM 8/21/2011, John Lauterbach wrote:
>Thank you for your help.  Shorting the engine end of the O2-sensor
>connector to ground makes the engine decrease RPM, run rough, and
>exhaust to smell rich.

That says ECU is at least approximately doing its job of closed-loop
mixture control.

>   Voltage on sensor end of connector is about 0.20
>volts.  When cable is not shorted, voltage goes up a bit to about 0.25.
>When both halves on connector are joined, voltage is about 0.45 volts.
>However, most of that voltage is present on the engine end of the
>O2-sensor cable.

I don't understand this statement, most particularly the last
sentence.  Could you expand/rephrase please?  If you're getting
different voltages at different points on the sensor cable then you
have a connection problem.

>   Does this mean something in the ECU is wrong?

Prolly not.

Yours,
David