Test results:
Bu/gn wire: at fist nothing, then gradual from 6.5 to 14.2 volts and steady at 14.2
Brown wire: nothing to ground, so 12v going through heater

Resistive tests with ignition off and connectors seperated:
Engine computer, brown wire to ground 0 ohms
Engine computer, Blk wire to ground 96.2 ohms

Oxygen sensor grey to white no continuity (bad heater coil?)
Oxygen sendor white to white 2.7 ohms

So I guess I do have a bad oxygen sensor heater? Would that cause the idle surges?

Please suggest an economical replacement part. I want online and an site lists four 4-wire units, two from bosh and two from other vendors which are much cheaper.