1. Fuel System Issues:
- Check fuel pressure and flow
- Inspect fuel lines and fuel filter for leaks or blockages
- Have your fuel injectors tested and cleaned if necessary
2. Air Intake System Issues:
- Check the air filter for obstructions
- Inspect air intake hoses and ducts for damage or leaks
3. Electrical System Issues:
- Check the battery and battery connections
- Test the ignition switch
- Have the alternator tested
4. Sensor Issues:
- Check the oxygen sensor
- Test the crankshaft position sensor
- Inspect camshaft position sensor
5. Computer Issues:
- Have the Powertrain Control Module (PCM) tested for faults
6. Transmission Issues:
- Check transmission fluid level and condition
- Have the transmission inspected for internal issues
7. Vacuum Issues:
- Inspect vacuum lines and hoses for leaks or damage
- Check for vacuum leaks in the intake manifold
8. Catalytic Converter Issues:
- Check for a clogged or damaged catalytic converter
9. Fuel Pump Issues:
- Check fuel pump pressure and flow
- Test the fuel pump relay and wiring
10. Engine Mechanical Issues:
- Inspect the timing belt or chain
- Check compression in the cylinders
- Examine the engine for any mechanical malfunctions
Recommendation:
Given the complexity of the potential issues, it is advisable to take your vehicle to a trusted mechanic or auto repair shop for a proper diagnosis and repair. They have the necessary tools, expertise, and experience to accurately identify and fix the problem, ensuring your safety and the reliability of your GMC Envoy.
