Intial testing new 4 wire gm O2 sensor

[Bruce Plecan]

For those new folks here, not all of the 4 wire O2 sensors have a isolated
ground, and some tomfollery came into play to find one that was.
  One of the things we been working on here at CSH, HQ is using a O2 sensor
as both the O2 sensor, and as a EGT Devise.  Well, preliminary testing just
validated it does work, now to expose it to some real world testing.   Lots
of things that may go wrong, but it's a start.
Bruce