GMC Troubleshooting Questions? Ask a Mechanic for Answers
How much fuel pressure did you get when testing?
How long has it been since the cap and rotor have been replaced?
These engines have a bad habit of building up moisture inside the distributor cap. Remove the cap and look for moisture or corrosion buildup. If you see any, go ahead and replace the cap and remove the screen in the base of the distributor housing. This will prevent future issues.
Let me know how it does. If you still get a no start but the engine will start on starting fluid, then I would suspect the fuel spider. Distributor cap is much easier problem to address first.