2005 Chevrolet Silverado Possible fuel pump out?

I have a 2005 Chevy Silverado 1500 crew cab 2wd 5.3 vortec... Last week as I was going down the road my truck out of nowhere started sputtering really badly not allowing me to give it any gas, when I put it in neutral for a second it calmed down, I would put it back in drive and it go smooth for about 5 seconds before sputtering again. I stopped, turned it off, turned it back on and drove fine for the rest of the day. It did the same thing the very next day, it also dispelled 1 very large cloud of black smoke smelling like sulpher, but that only happened once. After a couple days of doing this, it would only make it a couple miles down the road before sputtering very badly and then dying on its own where I couldnt start it again for at least 15 minutes, and when it would it would only run for about 2 or 3 miles. I went to autozone and had the check engine light checked, they told me cam shaft placement sensor so I replaced that along with much needed spark plugs. after replacing the sensor and spark plugs it fired right up, ran as smooth as ever for about 3 miles and then died. Now it only starts if it sits for at least an hour, it will run smoothly until the truck warms up, and then it dies now without any sputtering. It just goes from a smooth run to dead. I checked the fuel pressure, when the truck is cool it has great fuel pressure, after it warms up and dies it has no fuel pressure which is why Im thinking its not starting... What is causing this? Bad fuel pump? But is there anything else I might be missing? Also, I just noticed, when I first start it up, it sounds smooth, but as it gets closer to dying, there is a faint ticking noise that seems to be on top of the motor somewhere that gets louder until it dies.
Thanks