Where is the air fuel sensor on a Toyota 4 runner 2000?

On a 2000 Toyota 4Runner, the air-fuel sensor, often referred to as the oxygen sensor, is typically located in the exhaust system. There are usually two sensors: one upstream (before the catalytic converter) and one downstream (after the catalytic converter). The upstream sensor is generally found on the exhaust manifold or just after it, while the downstream sensor is located further along the exhaust pipe. To access it, you may need to lift the vehicle and work under it, depending on the specific configuration.