Rough Or Unstable Idle
- Check for A/C compressor continuous operation (always on).
- Check for A/C condenser fan circuit malfunction.
- Check for A/C relay circuit malfunction.
- Check for air charging pressure control system malfunction (Millenia 2.3L).
- Check for Camshaft Position (CMP) sensor malfunction.
- Check for Crankshaft Position (CKP) sensor malfunction.
- Check for damaged sensor ring on crankshaft pulley.
- Check for damaged sensor wheel on camshaft.
- Check for EGR system malfunction.
- Check for fuel injector malfunction.
- Check for Pressure Regulator Control (PRC) system malfunction.
- Check for fuel pressure regulator malfunction.
- Check for fuel pulsation damper malfunction.
- Check for fuel pump malfunction.
- Check for Idle Air Control (IAC) valve malfunction.
- Check for incorrect A/C refrigerant charge.
- Check for intake air system leak.
- Check for incorrect gap between CKP sensor and crankshaft pulley.
- Check for incorrect ignition timing due to Crankshaft Position (CKP) sensor malfunction or damaged crankshaft pulley.
- Check for incorrect valve timing.
- Check for low engine compression.
- Check for overheating engine.
- Check for PCV valve malfunction.
- Check for poor fuel quality.
- Check for Power Steering Pressure (PSP) switch circuit malfunction.
- Check for purge solenoid valve malfunction.
- Check for restricted exhaust system.
- Check for restricted fuel filter or fuel inlet sock.
- Check for restricted or plugged fuel lines.
- Check for spark plug malfunction.
- Check for spark plug wire malfunction.
- Check for Variable Valve Timing (VVT) system malfunction.