Cold Start Problem

OK, when my car sits for a few hours or sits overnight it is hard to start! When the car sits overnight it takes a while for the car to start like it is not getting gas, almost as if the fuel line is draining out and it has to pump gas back up to the engine. Its not as bad if the car sits for a few hours it only takes a little time to get it running. I have replaced the fuel pump in the car and the fuel pressure regulator seems to functioning (i have tested it by pulling off the vacuum line and the fuel pressure goes up to 40psi and when i put it back on the fuel pressure drops back down to 30psi) . Is there a check vavle on the fuel pump that may be bad or maybe somewhere in the system? i have also put a new fuel filter on the car too.

the regulator is working but it isnt holding the gas up in the fuel rail. Try putting the fuel pressure testor on it in the morning the pressure should be the same. if you prime the line up and let it sit you should not lose more then 5psi in 10 mins