As I'm reading about this a little to refresh myself I found something I had forgotten. The fuel pressure regulator can leak out of the vacuum line as well. I guess that can be diagnosed pretty easily by pulling the vacuum line off the regulator and turning the key on and seeing if fuel comes out.

Anyways, the whole idea is to not just replace things Willy Nilly on something like this. Someone will post on a forum that they've replaced the fuel pump, the injectors and got their fuel rails cleaned when the real problem is the fuel pressure regulator. Or they'll replace the fuel pressure regulator and the injectors when the problem is the fuel pump. With some very simple tools and some simple diagnostic procedures and a little reading you can avoid all that hassle. If all the fuel system components are good, then maybe look at the MAF sensor.