GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello I will help you with your question,
You will need to drive it until it quits again or let it heat soak after a drive and see if it will restart. When it won't start or when it dies you need to see the fuel pressure so you can install a gauge and have it ready or you can try spraying starting fluid in the intake and see if it tries to start.
If it does not start on spray then it is not a fuel problem but I think your fuel pump is dying.
If it will start on spray or shows no pressure on the gauge check for 12 volts and ground to the pump and if the pump has voltage replace the pump.
Please let me know how I can help