Where is the crankshaft position sensor located on a 1999 Ford F150?

The crankshaft position sensor (CKP) on a 1999 Ford F-150 is located on the passenger side of the engine block, near the bottom of the engine, behind the crankshaft pulley. You'll likely need to get under the truck to see it clearly. Access can be somewhat difficult depending on the specific engine (4.2L, 4.6L, or 5.4L). A shop manual or online diagrams specific to your engine would be helpful for precise location.