Where is the number 3 spark plug on a ford 4.6?

There's no universally consistent numbering system for spark plugs across all Ford 4.6L engines. The firing order changes, and the physical location of the plugs depends on the specific engine configuration (e.g., which year, whether it's a 2V or 3V engine, etc.).

To find the location of cylinder #3's spark plug, you must consult a repair manual specific to your year and model of Ford vehicle with the 4.6L engine. The manual will have diagrams showing the plug locations and firing order. You can usually find these online, through a parts store, or at a library.