I recently went to get the car I just bought smoged. It failed. Running to rich. Engine codes for O2 sensors. I changed the two out that are accessible from the hood. On top of each exhaust manifold. Now I’m working on the one just past the catalytic converter. I removed it only to find out it wasn’t even plugged in. I’ve searched endlessly for the missing connector. I’ve run my hands all up and down each wiring harness and found nothing. No connector and no broken off wires. The previous owner did lots of modifications to the point they put he has to put a new engine in before selling. He used it for racing and the mods he made would never pass smog. I suspect somewhere along the way the wires got clipped. I’m looking either for suggestions or photos for where it might be, or wiring diagram so I can run wires all the way back to where they started.