>  got the old one out and?connected the new
> one up and bus runs like crap. Rough idling
> with black smoke. Same as old sensor.
> Unplug it and it runs perfectly.

As I recall, when you disconnect the 02 sensor the ECU reverts to 'factory
default' mode rather than reading/responding to inputs from within the F.I.
system (temp sensor, etc.).  So by disconnecting the 02 sensor you're
actually changing the way the ECU acts in general. Therefore the actual
cause of your problem may be something other than the 02 sensor itself.
Disconnecting the 02 sensor is simply masking the problem by putting the ECU
into default mode.

- Ron Salmon
  The Bus Depot, Inc.
  www.busdepot.com
  (215)  234-VWVW

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