GM-GMC: not running, soda blasting equipment, gas gauge

Question
05 GM Express 2500 4.8 V8 just filled gas tank AND pulling trailed soda blasting equipment 7000 lbs. At stop sign it starts to stall and dies. so far we've replaced fuel pump in tank,(REAL NICE FULL TANK) fuel sensor, getting spark, pressure gauge test "good", ran scan (waiting for answer what code). GAS GAUGE READS 1/2 FULL. When we have sprayed starting fluid in carb it will run then die? The van Manual talks of fuel regulator turns off fuel @5600 rpm could this be the next item to replace or what would Mr. Goodwrench do?

Answer
The fact that when you spray fuel into the intake it starts indicates your injectors are not delivering fuel.  If you had a faulty fuel regulator you would not likely see the appropriate fuel pressure, which should be in the 60-65 psi range.  My next step would be to remove an injector connector and see if there is power and ground getting to the injector while the engine is cranking.  That will help you decide which direction to go.  If you have no power or ground you will need to diagnose the electrical side of the injector circuits, if you do have power and ground (a noid light should blink while cranking) and you are not getting fuel delivered, you will need to diagnose the fuel side of the injectors.
Hope this helps