is this part of the O2 sensor? are there other parts involved in this curcut other than the O2 sensor? will the O2 sensor replacement fix this problem???

 

The O2 sensor has an electrical element built in to heat it up faster on cold starts, and to keep it hot during extended idleing. Checking to see if the resistance of the two heater wires are within spec is the easiest way to be sure it is the problem. (I don't have a manual here, and don't remember the spec.) The O2 is usually the problem, although I have seen a few with bad wires going to the ECU.