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What Causes Rough Idling?

23 January 2020

A smooth-running car is every car owner’s dream. However, the moment you start to slack off on your car maintenance routine,  a major breakdown is bound to happen. There are a few ways you can foretell an impending breakdown and that is by noticing your car’s behavior. Is your car consuming more fuel? Is it losing power while accelerating? Usually, all these issues happen because you have a rough idling car.  So what causes rough idling? Here’s a list of common causes.

Faulty Spark Plugs or Distributor
A petrol engine has spark plugs in each cylinder that ignite the air/fuel mixture. As a result, the pistons move and consequently the car. If the spark plugs are misfiring or not firing at all then the combustion in the cylinders is not happening smoothly. This causes the pistons to move irregularly and your engine starts to gurgle. The smooth idling of your car turns into a battle of survival for the engine where it is constantly looking to stay alive rather than stalling. This issue can be solved by going for a tune-up and getting your spark plugs checked. They have a lifespan of 25,000 to 50,000 miles after which the old ones need to be replaced with new ones.

Another reason why your spark plugs may be misfiring is that your car’s distributor cap has gone bad. The distributor cap is charged with timing the firing order of the engine. Hence, its failure can prove to be the main reason behind a rough idling engine.

Bad MAF/MAP sensor
A Mass Airflow Sensor or MAF is tasked with regulating the amount of air entering the combustion chamber. It measures the air entering the engine and helps the ECU measure the amount of fuel that needs to be added to keep the A/F mixture perfect. If there is any fault with the MAF sensor then your engine will not be able to idle smoothly. Your car will consume more fuel, and combustion will not be pure. The problem can arise if the Manifold Absolute Pressure Sensor (MAP) is faulty as well. If anything goes wrong with this sensor, then the engine will not be able to idle smoothly and will probably stall. Fortunately, these sensors are easily replaceable.

Dirty air filter for car engine. Concept of automobile maintenance and serviceClogged Filters
Rough idling can also be caused by clogged up filters. The air filter is the first to get affected by the environment. All the debris and dirt in the air passes through the air filter protecting the engine from sucking up all the harmful elements. This filter usually lasts not more than 3000 miles, which is why you should replace it every time you go for an oil change. If you time your maintenance trips correctly your air filter will always be fresh and in perfect working condition. It is also not very expensive to replace so it is not like you are spending a fortune every 3000-5000 miles. Keep in mind, though, that you always use the original air filter sold by your car’s manufacturer as aftermarket air filters are either not good quality or too bad that they restrict airflow instead of maintaining it.

Low Quality Fuel
Another reason why your car may be experiencing rough idling could be due to the use of low-quality fuel. You should always check the grade of fuel recommended by your car’s manufacturer. For example, your car won’t idle smoothly if you use 87 octane when 93 is recommended.   

Gumout All In One Fuel System Cleaner with Ethanol TreatmentFuel System Problems
Your car engine needs a smooth flow of fuel to the combustion chamber to idle smoothly and work efficiently. If there are any issues with your car fuel system such as corrosion from carbon deposits, then your car is susceptible to rough idling. An easy solution is by using Gumout All-In-One- Fuel System Cleaner. When poured in the gas tank, it cleans the entire fuel system, removing carbon build up and keep your car running smoothly again.