Where is the O2 sensor located on a 1987 Monte Carlo ls 4.3 engine?

On a 1987 Monte Carlo LS with the 4.3L (262 cubic inch) V6 engine, the O2 sensor is typically located in the exhaust manifold, before the catalytic converter. There's usually only one O2 sensor on these older vehicles.

To be certain, you should:

* Consult your vehicle's repair manual: This will have the most accurate location and diagrams.

* Look at the exhaust manifold visually: It's usually a threaded sensor, and relatively easy to spot. Follow the exhaust pipe from the engine; the sensor will be in the manifold close to where the exhaust pipe begins.

Be careful when looking; the exhaust manifold will be hot if the engine has been running recently.