What it does: The IACV regulates the amount of air that bypasses the throttle valve when the engine is at idle. This helps to maintain a consistent idle speed.
What happens when it fails: If the IACV fails, the engine may stall when coming to a stop or idling. The engine may also surge or race when the throttle is suddenly released.
2. Throttle Position Sensor (TPS)
What it does: The TPS tells the engine control unit (ECU) the position of the throttle valve. This information is used to calculate the amount of fuel that needs to be injected into the engine.
What happens when it fails: If the TPS fails, the engine may stall or run poorly when the throttle is at idle or full open. The engine may also hesitate when accelerating.
3. Oxygen Sensor
What it does: The oxygen sensor measures the amount of oxygen in the exhaust gas. This information is used to adjust the air/fuel mixture so that the engine runs at optimum efficiency.
What happens when it fails: If the oxygen sensor fails, the engine may run rich or lean, causing it to stall or hesitate when idling. The engine may also have decreased fuel economy.
4. Mass Air Flow (MAF) Sensor
What it does: The MAF sensor measures the amount of air that flows into the engine. This information is used to calculate the amount of fuel that needs to be injected into the engine.
What happens when it fails: If the MAF sensor fails, the engine may run rich or lean, causing it to stall or hesitate when idling. The engine may also have decreased fuel economy.
5. Clogged Fuel Filter
What it does: The fuel filter removes dirt and debris from the fuel before it reaches the engine.
What happens when it fails: If the fuel filter becomes clogged, the engine may not get enough fuel, causing it to stall or run poorly at idle.
6. Vacuum Leaks
What they are: Vacuum leaks are holes or cracks in the hoses and pipes that carry vacuum to the engine.
What happens when they occur: Vacuum leaks can cause the engine to stall or run poorly when idling. The engine may also have decreased fuel economy.
7. Faulty Spark Plugs or Wires
What they do: Spark plugs create the spark that ignites the air/fuel mixture in the cylinders. Spark plug wires carry the electrical current to the spark plugs.
What happens when they fail: If the spark plugs or wires fail, the engine may stall or run poorly when idling. The engine may also have decreased fuel economy.
8. Low Coolant Level
What it does: Coolant helps to keep the engine cool.
What happens when it's low: If the coolant level is low, the engine may overheat and stall.
9. Engine Mechanical Issues
What they are: Engine mechanical issues can include worn piston rings, damaged valves, or a bad camshaft.
What happens when they occur: Engine mechanical issues can cause the engine to stall or run poorly when idling. The engine may also have decreased fuel economy or make unusual noises.
If your car is stalling or running poorly when idling, it's important to have it diagnosed and repaired by a qualified mechanic. The sooner you have it fixed, the more damage you can prevent to your car.
