The coax part is from the O2 sensor connector forward.  It goes into the wiring harness and emerges at the ECU plug.  This type of syndrome is becoming pretty common on the list.  I suggest that you check the continuity of this green coax wire.  Many listees including me have found that the insulation around the inside signal wire fails allowing it to ground out on the surrounding ground wire. These failures produce exactly the symptoms that you suggest and are often intemittent.  Bumps, water, wiggling the wire, installing and removing the sensor, all of these can cause the problem to come and go.  It's probably not the sensor itself, but the connecting wires.

Gary
  ----- Original Message -----
  From: Schmidt
  To: vanagon@GERRY.VANAGON.COM
  Sent: Saturday, March 10, 2001 9:55 PM
  Subject: o2 data addendum

  I have not yet tried the coax with microphone cable replacement as posted by another listee, but would like to.
  Can someone describe this fix to me a little better as I got kinda lost reading the previous post.  I don't really know WHERE this coax wire is.  When I dc'd my o2 sensor, it was NOT coax, but just a small gauge insulated wire that I dc'd at a spade-type connecter.  Elec is not my forte.
  Jay

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