Rough Idle
NOTE:
Unless otherwise indicated, see appropriate SYSTEM & COMPONENT TESTING
article for testing procedures.
- Check idle speed and ignition timing adjustment. See IDLE SPEED, IGNITION TIMING & IDLE MIXTURE RATIO ADJUSTMENT in ON-VEHICLE ADJUSTMENTS article.
- Check battery and generator circuit. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
- Check fuel pump circuit.
- Check injector circuit.
- Check IACV-AAC valve circuit.
- Check EGR system.
- Check electric throttle control actuator.
- Check ignition circuit.
- Check camshaft position sensor circuit.
- Check Mass Airflow (MAF) sensor circuit.
- Check A/F sensor one.
- Check Engine Coolant Temperature (ECT) sensor circuit.
- Check heated oxygen sensor one circuit.
- Check Throttle Position (TP) sensor circuit.
- Check intake valve timing control solenoid valve circuit.
- Check IACV-FICD valve circuit.
- Check main power supply and ground circuits.
- Check power steering pressure switch circuit.
- Check ECM.
- Check Park/Neutral Position (PNP) switch circuit.
- Check refrigerant pressure sensor circuit.
- Check electrical load signal circuit.
- Check air conditioner circuit.
- Check fuel pressure regulator system.
- Check EVAP system.
- Check PCV system.
- Check fuel piping and valve deposit.
- Check fuel condition.
- Check air duct and air cleaner.
- Check for air leakage from air duct.
- Check electric throttle control actuator.
- Check for air leakage from intake manifold, collector and gasket.
- Check cylinder head and gasket.
- Check timing chain and camshaft.
- Check intake valve timing control, intake valve and exhaust valve.
- Check exhaust manifold, tube, muffler, and gasket.
- Check three way catalyst.
- Check oil pan, oil strainer, oil pump, oil filter, oil gallery, and oil cooler.
- Check oil level and condition.
- Check radiator, hose and filler cap.
- Check thermostat, water pump and water gallery.
- Check cooling fan.
- Check coolant level and condition.
- Check cylinder block, piston and piston ring.
- Check connecting rod, bearing and crankshaft.
- Check hydraulic lash adjuster.
- Check cooling fan.