'86 CGT oxy sensor

[Craig D. Niederst]

With all this oxy sensor talk, I know my '86 CGT is in need of a new one. It
currently has a one wire sensor in it now. I noticed that while this 1 wire
sensor plugs directly into a single socket plug on the factory harness,
there is a 2 wire socket on the same harness that is unused. Does the '86
CGT take a 3 wire heated sensor, or is the 1 wire one correct? I've looked
in the family album, and its inconclusive. I am hoping replacing this sensor
will correct the horrible idle problems and the poor gas mileage (~12 mpg
according to the trip computer). TIA.

Craig
'92 100S (90k)
'86 CGT (191k)