Car Idling Rough Check Engine Light On

Causes

There are several potential causes for a car to idle rough with the check engine light on. Some of the most common causes include:

Vacuum leak: A vacuum leak can cause the engine to run lean, which can lead to rough idling and a check engine light. Vacuum leaks can be caused by a variety of factors, including damaged hoses, gaskets, or seals.
Spark plug problems: Worn or fouled spark plugs can also cause a car to idle rough. Spark plugs are responsible for igniting the air-fuel mixture in the engine, and if they are not working properly, the engine can misfire, which can lead to rough idling.
Fuel injector problems: Fuel injectors are responsible for delivering fuel to the engine. If fuel injectors are clogged or dirty, they may not be able to deliver the correct amount of fuel to the engine, which can lead to rough idling.
Ignition coil problems: The ignition coil is responsible for providing the spark that ignites the air-fuel mixture in the engine. If the ignition coil is not working properly, the engine may not be able to start or may idle rough.
Mass airflow sensor problems: The mass airflow sensor is responsible for measuring the amount of air that is flowing into the engine. If the mass airflow sensor is not working properly, the engine may not be able to get the correct amount of air, which can lead to rough idling.

Symptoms

In addition to rough idling, other symptoms of a car idling rough with the check engine light on may include:

Stalling: A car that is idling rough may also stall, especially when coming to a stop or when idling in traffic.
Hesitation: A car that is idling rough may also hesitate when accelerating, especially when starting from a stop.
Poor fuel economy: A car that is idling rough may also get worse gas mileage than usual.
Increased emissions: A car that is idling rough may also produce more emissions than usual.

Diagnosis

If your car is idling rough and the check engine light is on, it is important to have the car diagnosed by a qualified mechanic. The mechanic will be able to use a diagnostic scanner to read the trouble codes that have been stored in the car’s computer. These trouble codes can help the mechanic to identify the cause of the problem.

Treatment

The treatment for a car that is idling rough with the check engine light on will depend on the cause of the problem. In some cases, the problem may be simple to fix, such as replacing a vacuum hose or spark plugs. In other cases, the problem may be more serious, such as a faulty fuel injector or ignition coil. In these cases, the mechanic may need to replace the faulty part or parts.

Prevention

There are a few things you can do to help prevent your car from idling rough with the check engine light on. These include:

Get regular maintenance: Regular maintenance can help to keep your car running smoothly and prevent problems from developing. This includes getting oil changes, tune-ups, and other recommended maintenance services.
Use high-quality fuel: Using high-quality fuel can help to keep your fuel injectors clean and prevent problems from developing.
Avoid driving in extreme conditions: Avoid driving in extreme conditions, such as very hot or cold weather, as this can put a strain on your car’s engine.

Conclusion

If your car is idling rough and the check engine light is on, it is important to have the car diagnosed by a qualified mechanic. The mechanic will be able to identify the cause of the problem and recommend the best course of action.