what is wrong when codes say my fuel is running rich and oxygen sensor malfuncti on 2005 Audi A6 Quattro

i had autzone reset the codes and it hasnt happened anymore

Asked by for the 2005 Audi A6 Quattro
1 answer
If one of the O2 sensors fail it could read "rich" air fuel ratio on the bank of cylinders with the failed O2 sensor. Other things can influence a rich running condition, a failed fuel pressure regulator, leaking fuel injector, bad coolant temperature switch or air flow meter.