Does it run rough for a short time when it fires up? Or does it run smooth. Have you tried cycling the key a few times before cranking? Then does it fire right up?
Most of the time it's the fuel pump bleeding back. If you had a rough run for a few seconds then I would suspect a injector.
If you just have a external leak you could jump the fuel pump relay and let it sit with it not running while watching for leaks. This would pressurize the fuel rail but the danger would be if a injector was leaking you could potentially fill the cylinder with fuel.
2014 JKU, JKS lift,Poison spyder flares, bombshell covers,Rancho D2 control arms, JKS adjustable track bars, 35" Tires. GrabBars, Crawler Conceptz rear bumper, Smitty front bumper, Winch. Rough Country inner fenders, Teraflex Disco Mud Flaps
Backseat Dobermann Security