I purchased AC Delco oxygen sensor, single purple wire as recommended. I realized that the plug on my car is for 4 wires. The 02 sensor I pulled out of there was a NTK 4 wire unit that apparently is for a Jeep. What do I do? The purple wire on the car splices into the 4 wire plug (plug with blue). The wire from the 4 wire plug leads to this black box. Is this part of the alky system? What is this black box for? And then there is this red plug that was not plugged to anything. Should it be? All I was trying to do is replace my O2 sensor so my scanmaster would read correctly. Please help if you can.