I have the 4.3 'Z' engine. Do you know the correct engine timing?
Engine Ingition timing on 1992 GMC Sonoma
The timming would be 0 Degree. This would be when you disconnect the tan with black stripe Wire that is right under the heater blower insde the passenger compartment. Then set the timming. After you have completed that task, you will need to disconnect the positive battery cable to reset the computer.