LT1, need help

[Oklahoma]

I know that there are a lot of experts on here, and maybe I can get some help. I have a 97 Camaro with the LT1, the problem I am having is fuel pressure. When starting my fuel pressure would only go up to 40psi, but I would have to turn the key on several times to get it to that just for it to start. the fuel pressure would bleed back down as soon as the pump would kick off, after the 3 second it would come on for it to pressure up. I was told that the fuel pump has a check valve in it and it was bad, letting the fuel bleed back into the tank. so i replaced it, it worked good for about a day. now it is worse that it was before, it bleeds down faster, and it take about 15 seconds of constant cranking for it to get enough pressure for it to run, and still only around 40 psi running. could there be something else that is causing this, or did i just happen to get a defective fuel pump?
Thanks Guys.