1988 FJ62, stock engine, 280k. In the last year I have replaced both O2 sensors with OEM, replaced the TPS, tested the ECU (passed), replaced the distributor (OEM), replaced plugs and wires, fuel filter, fuel pulsation damper, and more. It has had smelly exhaust for a while and nothing has seemed to help. I am now getting an O2 sensor CEL. When I replaced the front sensor, I wired it the same way it was prior, but the wiring seems a little wonky and I would like to get the group's thoughts. Is this wiring correct? The rear sensor wiring still had the factory wiring connector, which makes the wiring obvious - 4 wires to 4 wires. The front one was wired with three of the wires going to individual wires heading to the harness, but the fourth wire from the sensor was connected to three brown wires that also headed toward the main harness. What gives? Shouldn't it also be 4-to-4? See pictures.
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