Where is the o 2 sensor bank 1 located on a 1999 Mazda?

On a 1999 Mazda, the O2 sensor for bank 1 is typically located in the exhaust system, upstream of the catalytic converter. It can be found on the exhaust manifold or just after it, depending on the specific engine configuration. For accurate identification, refer to the vehicle's service manual, as sensor placement may vary slightly between different models and engine types.