I have a 2007 Expedition thought the fuel pump.

Scan for codes and check to see if your evap valve is working

See if it getting power if it doesn't then it's'another problem but it will only work at certain time it really needs a smoke test to make sure no leaks as well. Also moight be plugged up

The pum is controlled by the pcm which sends a ground to the relay on start u thenis taken over by theoil pressure switch which tells thepcm to conitnue operation. If this has been hit recently check the inertia switch in left cargo corner. Yo may have a blocked return line if it doesn't get power there is abad connection between relay pcm switch etc. Either that or wire grounded out and now sending a signal. Blowing in the vent pipe which you are doing sholdn't effect it either way, if you aren't getting fuel pressure see if you are getting pwoer to pump if you are then the pump is bad which will require a whole new unit which the fuel tank pressure sender is included.