Don't know just how much help this will provide, but may clear up something.
I believe The fuel system on your vehicle has what is referred to as a returnless fuel system. That means there is no return line coming from a fuel pressure regulator that used to be located in the engine compartment. The pressure regulator is now part of the fuel pump module in the fuel tank. The fuel pump is controlled by a pulsewidth modulated system where the fuel pump runs only when necessary and can have different pressures as long as the engine is supplied with the amount of fuel actually needed.
There is still a filter in the line and do you know if that has been changed recently? It might help if you had Autozone check for any codes in the computer. It might provide some direction.
There should be a fuel pressure sensor on the fuel rail that is supposed to tell the system if more pressure is needed.
Last edited by hanky; 04-29-2012 at 08:36 PM.