## Fuel and Emissions Systems

#### Symptom Troubleshooting Index (cont'd)

11-173

Symptom | Diagnostic procedure | Also check for
Idle speed fluctuates (MIL works OK, no DTCs set) |

1. Test the fuel pressure (see page 11-131).
2. Test the injectors (see page 11-276).
3. Troubleshoot the ALT FR signal circuit (see page 11-120).
4. Inspect and test the PCV valve (see page 11-159).

- Contaminated fuel

Misfire or rough running (MIL works OK, no DTCs set) |

1. Check the spark plugs (see page 4-25)
2. Test the fuel pressure (see page 11-131).
3. Test the injectors (see page 11-276).
4. Troubleshoot the fuel pump circuit (see page 11-287).

- Low compression
- Valve Clearance
- Contaminated fuel

Fails emission test (MIL works OK, no DTCs set) |

1. Inspect the three way catalytic converter (TWC) (see page 11-300).*3
2. Check the spark plugs (see page 4-25).
3. Test the fuel pressure (see page 11-131).
4. Test the injectors (see page 11-276).
5. Check the EVAP emission control system (see page 11-305).

- Contaminated fuel
- Low compression
- Slipped/broken timing belt

Low power (MIL works OK, no DTCs set) |

1. Test the fuel pressure (see page 11-131).
2. Check the air cleaner element (see page 11-147).
3. Inspect/adjust the throttle cable (see page 11-149).
4. Inspect and then test the throttle body (see page 11-299).
5. Inspect the three way catalytic converter (TWC) (see page 11-300).*3
6. Test the injectors (see page 11-276).

- Contaminated fuel

Engine stalls (MIL works OK, no DTCs) |

1. Test the fuel pressure (see page 11-131).
2. Check/adjust the idle speed (see page 11-285).
3. Troubleshoot the brake pedal position switch signal circuit (see page 11-123).
4. Check the spark plugs (see page 4-25).

- Intake air leaks
- Faulty harness and sensor connections

*3: with TWC model