Where is spark plug number one on 2002 Ford F-150?

On a 2002 Ford F-150, the number one spark plug is located on the passenger side, front of the engine. However, the exact location will depend on whether you have a 4.2L 6-cylinder or a 4.6L V8 engine. It's always best to consult your owner's manual for a diagram specific to your engine. The manual will clearly show the firing order and the location of each spark plug.