The IAC valve controls the amount of air that bypasses the throttle plate when the engine is idling. If the IAC valve is faulty or dirty, it can cause the engine to stall at idle.
Dirty Throttle Body:
A dirty throttle body can restrict airflow and cause the engine to stall at idle. Inspect the throttle body for dirt and debris, and clean it if necessary.
Vacuum Leaks:
Vacuum leaks can cause the engine to run lean and stall at idle. Check for vacuum leaks around the intake manifold, throttle body, and other vacuum hoses.
Fuel Pressure Regulator:
A faulty fuel pressure regulator can cause the fuel pressure to be too low or too high, which can lead to stalling at idle. Check the fuel pressure and replace the regulator if necessary.
Oxygen Sensor:
A faulty oxygen sensor can cause the engine to run rich or lean, and either one can cause stalling at idle. Check the oxygen sensor and replace it if necessary.
Spark Plugs:
Worn or fouled spark plugs can cause the engine to misfire and stall at idle. Replace the spark plugs if they are worn or fouled.
Ignition Coil:
A faulty ignition coil can cause the engine to misfire and stall at idle. Check the ignition coil and replace it if necessary.
Fuel Filter:
A clogged fuel filter can restrict fuel flow and cause the engine to stall at idle. Replace the fuel filter if it is clogged.
