I found out that my harness from the car end was melted from coming in contact with the exhaust. I had to cut both the harness from the car and O2 sensor and re-spliced (and soldered) them together. Drove around for a bit and the CEL still came on with the same message.

I went ahead and ordered 4 new sensors, but I could've sworn I replaced the front passenger side one less than a year ago.

Now its a pain to replace the other sensor because I have to splice and solder the wires each time since both the harnesses are gone.

1997 Isuzu Rodeo S 4WD