Rough Or Unstable Idle
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 1995 Mazda RX-7, 1995 Mazda Protege, 1995 Mazda Millenia, 1995 Mazda MX-6, and 1995 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
- Use stethoscope to verify fuel injector operating noise.
- Ensure fuel system pressure is correct.
- Check EGR valve condition and operation.
- Verify ignition timing is correct.
- Check PCV valve.
- Check mass airflow sensor.
- Check coolant thermosensor for correct resistance.
- Check bypass air control valve.
- Check for cracks and poor connections (vacuum leaks) at airflow meter or throttle body.
- Check HO2S for fluctuating 0.1-1.0 volt output while increasing and decreasing engine RPM.
- Verify throttle position sensor adjustment and resistance value.
- Check purge valve function.
- Check for poor fuel quality.