1. Open the hood.
2. Verify the condition by operating the vehicle for a short time.

NOTE :

• Key symptom is elevated idle speed while noise is occurring.
• "Snapping" the throttle can induce the noise.

3. Inspect the ISACV. If physical evidence of contamination exists, install a new ISACV.
4. While the noise is occurring, either place an EngineEAR probe near the ISACV and the inlet tube, or create a 6.35 mm (0.25 in) - 12.7 mm (0.50 in) air gap between the inlet tube and the clean air tube. If the ISACV is making the noise, install a new ISACV.
5. Test the vehicle for normal operation.