You should check the fuel pressure. It is a common problem, the check valve inside the fuel pump leaks and wont hold the pressure. It takes a couple of seconds for the system to build the necessary pressure to start the engine.
You don't need to pump the gas pedal, just turn the ignition switch to the ON position for a 2-3 seconds and start the engine.
There is also a bulletin for the 04 models:
http://x.nissanhelp.com/forums/Knowl...pp=10&keyid=66