Update:
Code PO171 is gone and PO131 showed up. So we went from reading lean to having low voltage readings on the new sensor. I am going to replace the O2 sensor I installed (Borg Warner) with an AC Delco unit and monitor it. hopefully it was just a case of you get what you pay for... Also slathed some black rtv on the map sensor gasket since that slight tear may create a vacuum issue later on.
Anyone ever experienced a faulty O2 sensor causing idle fluctuations and surging/dying? I suppose if the readings were far enough out of spec in closed loop, then yeah it might throw the ecm for a loop like that. Im hoping this corrects it...
