 that's probably what's happening on the vehicle most people if you've got a catalytic converter that has had multiple failures like that if it's not clogging up but it's turning the light on they'll just leave it and they'll drive it that way as long as the vehicle's still operating well but you got to check engine light unfortunately but if it's burning oil that's that's what's happening now on the other hand with the oxygen sensor failing typically it's the heater that fails in the sensor