Fuel pump

I have 1999 chevy Slvdo 1500 5.3. I was told by a mechanic that I had a bad F-Pump there was lil pressure I replaced it but now I have no gas coming out of the line just lil air pressure and a few drops of gas that I think where in the line from before. My question what else can cause for gas not to flow I checked all my fuses there fine is there any other switch that can be cousing my problem I have power on my line to fuel pump so thats not the problem my new pump came with new wire harness that I replaced instrctions just said to color code the wires and I did but still dint work im thinking I dint have a bad fuel pump it might have been something else?
Any Advice for me to check something else