2002 Silverado start issues

Ok, heres the deal. I have a 2002 4.8l v8 Silverado. Its hard to start if it sits for a little while, example if it sits for an hour or sometimes less it cranks and cranks for about 10/15 secs and then starts. Sometimes i have to let it crank and crank stop and crank some more. I see people suggest fuel pressure regulator. I changed that yesterday. What are some other things that can do this BESIDES the fuel pump, since I have a new one I will be installing. Dirty throttle body?

if u have the new pump, my advice would be to not do anything else until u install it.i know for a fact the regulator is over $75 cuz i just put one in my truck.if u already have the pump and its paid for install it now.if thats the problem you'll be saving money, rather than keep buying things that u dont need.im going thru similar difficulties now, and i wasnt workin for 3 weeks so buyin a $350 sending unit was out of the question.im goin back next week so ill be able to do it.but my point here is the pump is a safe guess.and if u have one to put in do it.

If you can still get your money back on the pump, try checking the fuel filter first. Just in case. They're like ten bucks. If you've never replaced it, it probably needs one anyway.

I bought a filter, regulator, and pump at the same time. The filter and reg are replaced. I just wanted to know if there is anything else besides the pump.

you may want to try replacing plugs and wires. highly unlikely it would be those, but outside of those 3 things you mentioned, it is the only thing left except for the computer, which I would rule out until last.

I also have a 2002 4.8L that is doing the exact same thing that you described. I replaced the regulator and it helped for a while, then I replaced the fuel filter and it also seemed to help, but every now and then the engine will still crank forever before it starts. I hooked up a fuel pressure gauge to the engine, and the pressure bleeds down to zero after the ingition is turned off, this leads me to believe that it is a bad fuel pump. Let me know if you have replaced your fuel pump, and if that solved the problem. Thanks.