Engine Controls - Trouble Shooting - No Codes: Symptoms: Backfire
- Check ignition timing and ignition circuit.
- Check Exhaust Gas Recirculation (EGR) system.
- Check Camshaft Position (CMP) sensor circuit.
- Check fuel pressure.
- Check fuel evaporative emission system.
- Check Positive Crankcase Ventilation (PCV) system.
- Check Idle Air Control Valve-Auxiliary Air Control (IACV-AAC) valve and circuit.
- Check front Heated Oxygen Sensor (HO2S) and circuit.
- Check main power supply and ground circuits.
- Check engine mechanical condition.