Excessive Idle Speed In Neutral

1. Leaky idle control solenoid valve.
2. Leaky fast idle control solenoid valve.
3. Throttle body valve stuck open.
4. Fast idle mechanism adjusting screw out of adjustment.
5. Leaky fast idle valve.
6. Defective ECU.
7. On models with automatic transmission, leaky A/T idle control solenoid valve.