Where is the fuel rail on a 1998 Ford Explorer sport?

The fuel rail on a 1998 Ford Explorer Sport (assuming it has the common 4.0L SOHC V6 engine) is located on the top of the engine, at the rear (back) of the intake manifold. It runs roughly parallel to the intake manifold itself. You'll see fuel injectors spraying fuel into the intake manifold from it. However, accessing it will likely require removing some components for good visibility.