Where is the 5th spark plug on a 2001 Ford Expedition Eddie Bauer 5.4L engine?

The 5.4L Triton V8 engine in a 2001 Ford Expedition Eddie Bauer has only eight spark plugs, not five. There isn't a "5th" spark plug in the traditional numbering sense. The firing order determines which cylinder fires when, not a simple numerical placement.

To find the location of a specific spark plug, you'll need a repair manual or a diagram showing the firing order and plug locations for that specific engine. These usually number the cylinders from 1 to 8, and show where each plug is in relation to the engine block and valve covers.