2002 GMC Sierra No go

I have a '02 Sierra 1500HD (6.0l V8) that won't start. Over the last 6-8 months it has occasionally stumbled while at highway speed (set code for "primary fuel circuit failure"). Three months ago I changed the fuel filter and the fuel pump relay and the problem seemed better even though it continued to set the code. The engine stalled completely while at speed last week but started right back up and ran normally until it failed to start on Friday. I took off the fuel filter, dumped it out and found a goodly amount of fine black "silt" in the gas. Turned on the ignition key 4 times while the fuel line was disconnected and got 3 brief squirts of gas. Nothing on the 4th. I think it is fuel pump and another tech thinks it is the computer. Both parts are expensive and I would like your 2 cents- would you lean towards the fuel pump or the computer?