GMC Troubleshooting Questions? Ask a Mechanic for Answers
I am sorry your having this problem
when it will not start i am assuming the engine is physically cranking over and not fire up ?
if so when it will NOT start will it somewhat run on starting fluid being sprayed down the throttle body butter fly ?
do you have spark at the spark plugs when cranking it over ?
when these will not start it comes down to we need to see if it is missing spark or fuel
once we know which is missing then we can go after why its missing spark or fuel
if its missing fuel a fuel pressure gauge needs to be connected to the test port on the fuel rail under the hood and we need to know what the fuel pressure is key ON engine OFF