After fuel fill and cap removal 2003 996 won't start without cranking a few seconds. Ideas?

Your fuel pump is on it's way out. it's common to happen in the winter time when your gas tank is low on fuel and gets refilled. What happens is the piston in the electric fuel pump wears after a few years of service, as the amount of fuel in the gas tank will moderate the temperature of the fuel pump. When gas is added in the winter, the gas is much colder and makes the piston and cylinder sleeve contract since it's made of plastic will contract much faster and when the fuel pump is reactivated. The clearance between the piston and cylinder have a lower tolerance, causing the fuel pressure to drop. This is why you may have to energize the fuel system twice by turning the ignition keys on "engine not running" for 5 seconds and then turning it off again and turning it on again for 5 seconds and then start the engine. You can have the garage check the fuel pressure and check the pressure bleed down time, which would help indicate for you to replace the fuel pump. But start with the simple and replace the fuel filter, this may get you more life out of the fuel pump. Good luck and hope this helps, keep me posted nad please rate.