Where are the O2 sensors in a 1997 Lexus ls400?

In a 1997 Lexus LS400, there are typically four O2 sensors located in the exhaust system. Two are positioned upstream (pre-catalytic converter) and two downstream (post-catalytic converter) of the catalytic converters. The upstream sensors monitor the air-fuel mixture, while the downstream sensors check the efficiency of the catalytic converters. Accessing them usually requires lifting the vehicle for better visibility and reach.