The O2 sensor tells it like it is. If there is unburned fuel in the exhaust flow that the pre-cats would have caught, the O2 sensor will communicate such to the ECU. I don't think it will be a problem since those pre-cats can't be very effective even when new.
You'll likely get a check engine light if you remove a cat that is between two O2 sensors.
Sixto
91 300SE
87 300SDL
|