If it does turn out to be your O2 sensor, I do recommend you get the generic and splice it in. I have good results with mine using crimp connectors and covering with the heat shrink wrap tubing available at parts stores. It does get wet down there. They say not to solder them because these zirconia sensors "breather" through the wire insulation tube.

Oh, and yes, the white wires are for the heating element and it doesn't matter which way the current flows so the wires are interchangeable.
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Andy in St. Paul, '91 745 Regina 198K mi, '89 244 141K, '87 245 RIP