I was poking around the engine compartment trying to find a wiring problem (O2 sensors not getting power). I was looking at the "Salt and Pepper" wiring connectors to see if they were dirty when I noticed that I seem to have 4 of them rather than 2 (looks like one plugs into another via a short pigtail). All of wiring diagrams I have found only show 2 of these connectors... Anyone know why I would have 4?