won\\\\\\\\\\\\\\'t stay running

Hi, i have a 1989 f-150,6 cyl, 5 speed manual trans,dual fuel tanks
my problem is that the truck starts and runs for 1 or so mins than shuts down,
here\\\\\\'s what i\\\\\\'ve done replaced: low pressure pumps in both tanks ,new front tank,new hi pressure pump in frame rail, new distributor modjail, rotor,cap,wires, new coil, new fuel relays,new oil pressure shut off sender, sea foam in both fuel tanks.
engine starts,fuel pressure @ the rail is 42 psi, runs 1 or so min that pressure falls to 12 psi eng stops, won\\\\\\'t start for about 1\\\\\\\\2 hour or so,than same thing.
any one know anything else i can do?
Thanks,truckerkit

Pressure that starts at 42 and sinks to 12 while the engine runs means the supply isn't keeping up, and the half hour wait before it will start again is a big clue. That pattern often means the tank can't vent: the pump pulls a vacuum in the tank until fuel stops flowing, then it slowly equalizes while the truck sits.

Easy test: next time it dies, loosen the gas cap and listen for a hiss, then try to start it. If it starts, look at the cap and the tank vent and evap lines. If not, check the fuel tank selector valve (a common failure on dual tank trucks of this era), the frame filter, and any rubber hose that could collapse under suction.

Dana