1988 Chevy Cheyenne

I have a 1988 Chevy Cheyenne. Yesterday I had a crack in my passenger side tail pipe so I took it up to my friends shop and we welded it back together. Prior to this however, my truck was sputtering real bad and acting like it wasn't getting any gas. I need to do a tune up on it real bad. At first I was thinking it had to do with the cracked tail pipe but now it is ten times worse I can't even get it to go because it won't get enough gas. Do you think it's a fuel pump? Or what. And if so how much do you think it would cost me to get one for my truck?

I appreciate your help very much and anything you can tell me would be helpful, because I am clueless right now!

Brandyn