2001 fuel problem

I have a 2001 grand am gt with a 3.4 auto. While backing out of the driveway yesterday it just quit, would not restart. I did a spark test, it was good, then sprayed some starter fluid in the throttle body and it started up and quit. I can hear the fuel pump working as it should but there is 0 pressure at the fuel rail. I was thinking it could be the fuel filter restricting the flow but would it stop that quickly? running good one day and not the next? It has 70,000 km (42,000 miles). Could it be the pump even if it is still running? How hard is it to change the pump? I have heard you can access the pump from under the rear seat with out taking the tank out, don't know if it is true.

Try the fuel filter first. Fuel pressure at the rail should read around 59 psi with vacuum on at the fuel pressure regulator. Higher with the vacuum line disconnected. If the fuel filter doesn't cure it then the other possibilities are the fuel pressure regulator or fuel pump. The gas tank has to be dropped to remove the fuel pump assembly.

thanks for the info!! Can anyone tell me where to locate the fuel return line on this car? Is there a section of rubber line I can pinch off to do further testing??