won't start

replaced fuel pump in tank because before I did so, the vehicle would stall and if I kicked the tank, it would start and run for about 30 - 60 minutes before needing to do so again. So on the advice of a co-worker, I replaced the fuel pump in the tank. I know that there is another one under the door on the frame (driver's side), however, after I replaced the one in the fuel tank, the truck started and ran for about 10-15 minutes, yet since then I can not get it to start at all. I reset the shut off switch, and I checked all the lines and did the repairs needed.

I am not sure that the one under the door should be replaced as I did not have the failure to start until after replacing the one in the tank...

What should I do ???