fuel pump ?

[cablek9]

Have 2000 7.3, fuel pump on frame runs 20-30 seconds when key is first turned on everytime. truck loses power under load climing hill and on hard acelaration on top end. Replaced fuel pump still runs along time each time key is turned on. Is there a check valve that keeps presure at fuel filter res.?

[tubular031]

Have you changed the fuel filter yet? They are suppose to be changed every 10k. I would get a fuel pressure gauge and hook it up like this:

Fuel Press

this will give you an idea if your fuel pressure is the issue. Could also be a weak HPOP.