1998 Ford Ranger stalls/dies

I have a 1998 Ford Ranger with 112k miles. The truck will start, but will die after about 3 minutes. If I hold the RPM's steady It sounds ok. Also when I drive it, it has no power. As I shift from 2nd to 3rd you can really feel the lose of power. When I am going up-hill I have to shift down no matter what % the grade is. Also when I come to a stop, the engine will die before I come to a complete stop. I have replaced the fuel pump and the filter and the problem still exist. I disconnected the fuel line after the filter and I have fuel flow when I turn the key to allow the pump to pump. I removed the vaccum line from the fuel pressure regulator while the truck is running during the 3 minutes it will stay running and the truck starts dieing. When I put my finger over the vaccum connection at the manifold, I feel suction and it runs the same as if I did not disconnect the vaccum line. The pressure test valve on the fuel rail has NO pressure at all. Whether its running or not. Can this problem be the "Fuel pressure regulator"? I also should mention that there is NO check engine light on.