Possible Causes
- Front HO2S deterioration or malfunction.
- Fuel pressure regulator malfunction.
- Fuel pump malfunction.
- Fuel return line plugged or restricted.
- Misfire.
- PCV valve malfunction.
- Pressure Regulator Control (PRC) solenoid valve malfunction.
- Purge solenoid hoses improperly connected.
- Purge solenoid valve malfunction.