At 20:19 11/19/2016, Neil N wrote:
>Along with Davids comments I'd suggest visually inspecting the inner
>lead of the O2 green coax near the connector on body portion of
>harness. I see the warm start issue was present before the O2 sensor
>was swapped out, but a break at the inner wire casing can allow
>strands of the coax shield to touch the centre lead. This fault could
>be intermittent. A little WD40 makes it easy to slide back the rubber
>boot at the connector.

Yes, the place it shorts is under the connector boot where the shield
is cut back to expose the inner wire.  The sudden change in stiffness
causes a stress concentration and the insulation breaks at that
point, exposing the wire to stray strands of the shield braid.  Even
so, the ECU shouldn't be in closed-loop during startup, even with a hot engine.

Yrs,
d