Rough Or Unstable Idle
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Mitsubishi Outlander, 2003 Mitsubishi Montero Sport, 2003 Mitsubishi Montero, 2003 Mitsubishi Lancer, and 2003 Mitsubishi Galant. However, it is still accessible from the selected car via links, so may be relevant.
- If battery was recently disconnected, start and idle engine for 10 minutes, then recheck idle.
- If hunting, clean throttle body.
- Check Idle Air Control (IAC) motor.
- Check for vacuum leaks.
- Check PCV valve operation.
- Check EGR solenoid system.
- Check for injector operation sound.
- Check fixed Speed Adjusting Screw (SAS).
- Using scan tool, check closed throttle position switch (if applicable), IAT sensor, BARO sensor, ECT sensor, EVAP purge solenoid, EGR solenoid, front and rear HO2S, power steering pressure switch, A/C switch, Park Neutral Position (PNP) switch and IAC motor position values.
- Check fuel pressure.
- Using scan tool, perform actuator tests for EGR solenoid and purge solenoid.
- Check ignition system.
- Check purge control system.
- Check compression pressure.
- Check for fuel contamination.