Yesterday, I drove over to a friends house maybe 5 miles away, to pick him up, pulled in and shut off the truck. We where ther for maybe 30 mins, went back out to the truck, and his little bro wanted to hear it so I tried to start it, would not fire. I toutched the gas a little bit and it wanted to fire but wouldnt start, then it caught and took off. Could this be the fuel pump going? if so, how hard it it to swap out and how much would a pump cost?