2005 silverado fuel issues

Have a 2005 Silverado 4.3l v6 engine. Truck only has 100k miles and has not had heavy usage. Truck was not started for one week and now will not start. Truck does have gas. Truck turns over, but no start. I have replaced the battery as it got weak from all of the attempted starts. I verified spark on all 6 plugs. I checked all fuses including fuel pump relay. When the key is turned, you can hear the pump cycle on. Checked fuel pressure on rail near carb with key on, 50-55 psi. I tried to start by spraying starting fluid into the carb, but still not start. According to the book, I should have 60-66 psi on the fuel line. Is there anything I am overlooking? On this model, both the fuel filter and fuel pressure regulator are located in the tank with the pump. Find it hard to believe it is the pump with so few miles? Any other ideas?