The upstream oxygen sensor (also called Sensor 1) is mounted before the catalytic converter, typically in the exhaust manifold or just after it.

We earn commissions from purchases you make using links in our articles. Learn more. If your car experiences poor fuel economy, lacks power, feels sluggish, idles rough, or has an illuminated check ...

While O2 sensors have no fixed replacement schedule, your driving style and the health of other engine components can ...