Oxygen Sensor (O2) for V6 Pentastar UPSTREAM (2pc)When installing any performance modification you want fresh O2 sensors installed to deliver accurate data to the vehicle's computer. Included 2pc UPSTREAM sensors (before the catalytic converter) An O2 sensor in a car plays a crucial role in monitoring the level of oxygen in the exhaust gases that are emitted from the engine. The O2 sensor in a car monitors air fuel levels in the exhaust. It sends this data to the engine control unit (ECM), which