since you have a new pump, i would still check the pressure, like Fbody says, new doesn't always mean good... and also change to metal line. Vikki's bicycle pump trick sounds neat. your problem has me fairly stumped. if you are using winter fuel, or fuel from a particular station, i would change it. cold weather fuel is engineered to be more volatile at lower temps. oldtimers used to put wooden clothespins on their metal line to help cool it.

if you change to electric pump, you need to either find a wire which delivers 12v in 'start' and 'run', or wire directly to battery, incorporating a fuse and an on/off switch, which can double as a kill switch/anti-theft device. an electric pump will also require a pressure regulator to keep the pressure from getting too high.