If you tested for fuel at the shcrader valve, which is located on the main fuel line located in between the fire wall and block. You can't miss the fuel lines. You should have fuel come out with the ignition on and the center valve piece of it depressed. If non is coming out. Then you got a problem with your fuel pump, ie not the wires not plugged in, bad fuse, or relay. Worse case, a bad fuel pump.
This link might give you a little help. It is referencing to trouble shooting a no start possible bad fuel pump when having a spider valve injection system, which I do not know if that's what kind of injection system your vehicle has. Either way you can use this guide and it will work the same.
http://troubleshootmyvehicle.com/gm_...ump_test_1.php
GM ran a couple different fuel injection systems around then. If you could tell us which, if would be helpful in the process.