My names Shane, I'm in Ohio, and I have a 1995 f150XLT 2wd with the 5.0

Okay, about a month ago I was pulling out of a McDonalds and my truck just died. It took a few trys of about 10 second cranking to start back up, and died again. So I got it started, and reved it to the moon and took off. Then it acted completely fine.

About two weeks ago the problem changed to not wanting to fire. It would just crankcrankcrank. And about a few trys it would fire up. And one day it wouldnt even turn over. Tapped the starter with a hammer, it fired. So I replaced it. But I still had the problem with the crankcrankcrank. So I figured it wasn't getting spark. I replaced the plugs and wires, which I havent replaced them since I've had the truck, about 2 years.. And who knows when the last time they were changed.
It fired right up yesterday after changing the plugs. This morning, it's super foggy. So it's wet. And it would just crankcrankcrank, fired up. Pull into work, and it just died. Go to start it up, and crankcrankcrank, few trys it fired. And my check engine light was on.

Does anyone know if its a PCV valve, or is it possibly a fuel pump? Im thinking my gas is getting sucked back into the tank.
Thanks. (: