THAT IS A HEATED O2 SENSOR , before putting in a new one try this, pull fuse no 6 and see if it makes any diff , this is the fuse to the heater in the o2 sensor, if the sensor shorts internally they will do some strange thing s and it is not uncommon , they can drive the eng rich or lean, if no difference just unplug the o2 sensor , this will throw the eng in to a fail safe or limp mode as it is called,and the ecm will ignore all but 2-3 input signals ,the eng will run fairly decent but you will have a cel on, allso don,t forget the fuse it controls the wiper frt and rear and the washer Jerry