My 98 f150 won't start most of the time when it's 20 or below outside but once it starts warming up starts fine. I've tried fuel treatments to no avail. This morning i checked the valve on the fuel rail and there was no pressure with the key on. I did not hear the fuel pump either when i initially turned the key. Does this sound likea fuel pump starting to go bad or maybe a relay? If it stays warm out I never have a problem.