On a 1992 Chevrolet Lumina with the 3.0L V6 engine, the crankshaft position sensor (CKP sensor) is located on the
passenger side of the engine block, near the
bottom of the engine,
close to the oil pan. It's typically mounted on a bracket or directly to the engine block itself. You'll likely need to get under the car to see it clearly.
It's a small sensor with a single wire connector. Because of its location, accessing it might require some maneuvering and potentially removing some components for better visibility. A repair manual or online diagrams specific to your year and engine would greatly aid in pinpointing the exact location.