Where is O2 sensor located on 98 Acura TL 2.5?

On a 1998 Acura TL 2.5, the O2 sensor is located in the exhaust system. There are typically two O2 sensors: the upstream (pre-catalytic converter) sensor is found on the exhaust manifold, while the downstream (post-catalytic converter) sensor is located after the catalytic converter. You may need to lift the vehicle for better access to the sensors.