To be absolutely certain, you should:
* Consult your owner's manual: This is the best source for precise location information specific to your vehicle's trim level and engine type.
* Check a repair manual (like a Haynes or Chilton manual): These manuals have diagrams showing the exact sensor locations.
* Look under the car: The sensor is usually on the exhaust manifold or pipe near the engine. It will be a threaded sensor with a wire lead connected to it. Be cautious when working under the car and let it cool completely before inspecting.
Without knowing the specific engine in your Cavalier (e.g., 2.2L, 2.4L), pinpointing the *exact* position is difficult. The above advice is the most reliable method for finding it.