Where is the crankshaft position sensor on a 2003 Chevy Tahoe with 5.3L?

On a 2003 Chevy Tahoe with the 5.3L engine, the crankshaft position sensor (CKP sensor) is located on the passenger side of the engine block, near the bottom, behind the harmonic balancer (or crankshaft pulley). You'll likely need to look from underneath the vehicle to see it clearly. It's a relatively small sensor with a single-wire connector. Be aware that accessing it might require removing some components or at least maneuvering carefully.