Improper Idle Speed

1. Improperly adjusted accelerator cable play.
2. Clogged pressure sensor vacuum passage.
3. Faulty throttle opener system.
4. Faulty Idle Speed Control solenoid valve control system.
5. Faulty A/C Vacuum Switching Valve.
6. Improperly adjusted idle speed adjusting screw.
7. Faulty air valve.
8. Improper fuel pressure.
9. Faulty injector.
10. Poor performance of Water Temp., Air Temp. or Pressure sensors
11. Faulty ECM.