every once in a while my 2000 mustang v6 wont start. i noticed that when this happens, i dont hear my fuel pump pressurizing when i turn the key. I keep trying to start it, turning the key all the way off, then turning it on trying to listen for the pump to pressurize so i can start it. Once the pump pressurizes the car start fine. My question is, does anyone know whats going on? is the pump going out? should i just replace the pump? Whats the best way of detecting the exact problem and fixing it?