!!!!!help!!! Gas Leak!!!!

I have a 97 cheyenne V8 5.7L with 128,000 miles. Runs good for the most part. Recently, I dropped the gas tank to replace the fuel pump and found out all I needed to do was change the fuel filter which costs 5$. I wish I would have known that before I put in 8 hrs of labor gettin the damn tank off!! Anyway, I put everything back together and I went to fill up with gas and gas was leaking underneath the tank. Only thing I could think of is the main hose connecting to the tank itself. I tried moving the hose and tightening the clamps, but it still leaks. Was wonderin what the heck I need to do to fix this. I can't even fill my tank up without gas going everywhere. Other than that, it is fine. Just when I fill up is the problem. Was also wondering if there was any cheap easy ways to enhance the performance and get more horsepower and better gas mileage. It idles jus a tad rough ever since I had a head changed. Used to idle perfect but now it jumps a bit at idle but runs just fine. Maybe I can adjust the idle a little higher to see if that would help. ANY SUGGESTIONS???? THANKS for reply.

have you checked the hoses you disconnected? The large hose that runs from the gas fill door to the tank sounds like what you have left loose. No easy fix but to check what you did.... loose clamps and hoses

So, if I read this right it only leaks with a full tank and say you were to run it down to 1/2 tank and fill it to 3/4 would it still leak fuel?? Or is it leaking only when you're putting fuel in it?? If it's leaking only on a full tank I'm thinking you maybe you didn't get the seal right on the new pump.

If you are having a lot of trouble finding the fuel leak. You should pull the bed off. It's a hell of a lot quicker and much easier than dropping the tank. The hardest part is loosening the 8 bed bolts. They have some locktite on them so you will need a fairly long braker bar.But its worth the trouble. They will come out a lot easer if you put heat to them but I wouldn't chance it with a gas leak. After that its a couple of plugs for the lights and the three filler neck bolts.You will need at least three guys to lift it off .Then you will have an unobstucted view of everything and you can get a good look at your brake lines and replace them to if they are rusty.
It may sound like a pain it the way to go.

Just wondering, what makes the gas tank so troublesome to remove on a truck? I've removed and/or replaced the gas tanks on a few GM RWD B, C & FWD C body, and even a 79 Lincoln Mark V, and had no real problem even if everything was rusty. Just remember, if it's rusted, you might as well replace, so don't waste time trying to remove rusted straps & bolts; just cut them and use new parts.

BTW, three of my friends and my father-in-law are mechanics, and the rest of my friends don't own any tools what so ever, so at the first sight of a car repair, they all run away. There's isn't a hope in h@#$ that I could get a hand to remove the box :-).

sounds like you might have not goten the O ring in right or maybe it moved on you...good luck..

The worst part of removing the tank is the lack of room to manuver it out of the truck. the brakets and drive shaft are in the way and its difficult to reach the connections on the fuel pump. In my opinion you aren't saving any time trying to do it with the bed on the truck. And you can do a much better job standing on the side of the tank instead laying of under it. And like I mentioned before you can get a good look at the rear brake lines and do a nice job replaceing them if need be. If you take a look at 90% of the posts about R&R fuel pumps they say pull the bed. I have done it and its pretty nice way to do the job right.
P.S. you will only need Buddies for about 2 min. total to remove the bed and put it on some saw horses or some sort of support on the rails.Don't put it on the ground or you could bend the sheet metal.