Surging idle....only when car is rolling?

[Coupelx]

M50v in my 86 eta-
Ive been chasing this for awhile now. It originally only did it when the engine was cold, when warmed up it was fine. It has now started occasionally doing it when the car is warm. once you come to a stop the idle will work its way down and settle out. The speed sensor input is hooked up and working obviously. Pulled codes and only got an 02 sensor code, which is weird since it is somewhat new. But I dont think that would explain the idle issues while cold? all vacuum lines are new along with any and all orings and i cant find any leaks anywhere. ICV is clean.

Any ideas?

[Coupelx]

Update-

Replaced the o2 sensor with an ebay cheapy for testing purposes with no change.

Today i dug into the o2 sensor wiring and discovered that i had 12v on the signal pin in addition to the one for the sensor heater. Looking at the old o2 sensor the wires had shorted out inside the sleeve and melted the wires going back to the DME. a little solder and some heat shrink and all is well. no bouncy idle!