It does sound like a possible fuel pump, but it could be a bunch of different things. Did this problem start before the new fuel pump, right after the fuel pump or did it just recently start.

 

Wouldn't think it would be an O2 before it's running unless you have fouled plugs. Did you check the codes? Fuel pressure? Fuel filter? Regulator?

 

Any CEL codes ?
When was your last spark plug inspection and what brand & size plugs are you running ?
When was the last time you ran some carb/injector cleaner through your fuel system ?
A new fuel pump pumps the gas through the fuel lines but the injectors control your fuel spray.
If I were you I'd start with pulling a few spark plugs and inspecting their condition using a spark plug chart.

It could be something simple or a number of things causing your issue.

 

HEy guys sorry been busy . I have gotten some sensor codes before but it's been a while since I have had it checked I don't have a code reader of my own . So that's why I was leaning toward the O2 sensor deal

 

Take the truck to Autozone or O'reilly's or one of the local chain stores and they can read it for you for free. Good luck!

 

Fuel pressure regulator is a common problem with your generation that will cause your truck to rarely start on the first crank and can be a fairly simple fix. You can normally rule that out by priming your fuel pump a couple times before you start cranking.