Sometimes the codes that refer to the oxygen sensor, refer to the catalytical combination, but do not directly affect the resenti, the vehicle reveals accelerated and then lower to 850 rpm more or less, check your rementi regulator, in the elantra it is commanded by water temperature and bother much, since you have to check the water level, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat, the thermostat motor refrigerant. He had to disconnect it once the vehicle is at working temperature, disconnect the Rerenti regulator.