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A big part of car maintenance involves listening to the sounds that your vehicle is making and taking action whenever it is needed. Your engine is obviously one of the most important parts of your car, and it should purr along nicely. However, if you start to notice some coughing and spluttering sounds, this is a clear sign that something isn’t right.

A smooth engine needs exactly the right mix of fuel and air, so it could be that the balance is off. There are many parts of a car engine where the fuel and the air may not process properly, so engine spluttering could be an indication that something is off with one or more of these components. While some of the causes are simple and easily fixable, there are also others which are more complicated. An accurate diagnosis from a professional car mechanic will let you know what is going on and how best to fix the problem.

car engine

Take Note of the Conditions

It is also worth noting the conditions when your car engine seems to be struggling. Maybe it happens after the car has been parked for hours at a time, or perhaps it seems to be occurring constantly. Are there any other symptoms that accompany the spluttering? For example, have you noticed smoke being emitted from the exhaust as well? Take note of anything else which you think may be worth reporting to your mechanic. Even the details which appear minor and inconsequential may end up being highly useful.

Modern Vehicles Have the Edge

As vehicles continue to advance and develop, their technology improves as well. Modern engines will monitor their own fuel, combustion and exhaust systems. Generally, this is to ensure that emission controls are working correctly. You may find that your ‘check engine’ light is illuminated. Mechanics often have an easier job checking modern car engines, but there are also plenty of common signs which can be checked on older vehicles as well.

Common Causes of Engine Spluttering

There are a variety of issues which could be the cause of your car engine spluttering. Here, we will run through each of them one-by-one, as well as some of the ways that can be fixed. While some repairs are relatively straightforward, others are likely to require the intervention of a professional.

Dirty Air Filter

Your air filter has an important function in your car’s engine. It is designed to prevent debris, dirt, bugs, dust, pollen, and other substances from entering your engine. Many air filters have a folded paper element, and over time, this will become dirty and clogged. When this happens, it will not function as effectively as a brand-new filter. Many car specialists suggest replacing the air filter annually or after a certain number of miles have been driven (generally between 12,000 to 15,000), but your car’s manual should give you more information on this point.

Just as getting enough fuel is essential for your engine’s smooth operation, so too is getting enough air. If your filter is not functioning properly, it will reduce airflow into the engine, which can cause the spluttering sound which we are talking about. Other possible issues include a reduced fuel economy, lessened horsepower, and a strong smell of fuel.

A simple visual inspection will tell you the condition of your air filter. A brand-new filter should appear in a white to off-white color. Over time, this will darken, and debris may start to build up too. However, some contaminants such as dust and pollen are not so easily seen. Other signs which your air filter needs changing include a misfiring engine, smoke from the exhaust, and a rough idle. If you drive your car in dirty and dusty environments or frequently stop and go, it is likely that your filter will need to be replaced more often.

Changing a dirty air filter is relatively cheap and simple. It is located near to the top driver’s side of the engine in a rectangular plastic housing which usually snaps, or screws shut. As for older vehicles, they usually have a carburetor with a circular filter atop the engine that fastens with a wingnut. Choose an air filter replacement which is correct for your specific make and model of vehicle. Remember to clean the filter housing to get rid of dirt which has accumulated there.

Not only does replacing the filter often fix the spluttering engine issue, but you can improve your gas mileage by as much as 14%, and acceleration by up to 11%. And this means fewer trips to the gas station and an all-around better driving experience. So, pay attention to that air filter and learn some of the common signs that it needs replacing.

car engine check up

Old Spark Plugs and/or Ignition Wires

Another potential cause of your car engine spluttering is old spark plugs and/or ignition wires. As it implies in the name, these components provide the spark which results in internal engine combustion in your vehicle. The wires transmit electricity from the ignition coil to the plugs, which causes a spark to ignite the fuel and oxygen mix. In turn, this drives the pistons. The more you drive your car, the more unburnt gases and oil create a carbon residue on the spark plugs. Not only does this reduce the performance of the engine, but it can also cause strange noises and spluttering.

Spark plugs tend to last for around 30,000 miles, while ignition wires can last twice this length of time. Obviously, these figures depend on your driving style and how well the components are looked after. As part of your regular maintenance plan, you should have them checked, cleaned or changed as needed.

As well as the strange engine noises, there are a few other signs to watch out for. If you have trouble starting your car engine in the morning, old plugs may be the reason it is not getting the spark it needs. Otherwise, the engine may misfire from time to time. Also watch out for a higher-than-normal fuel consumption and lack of acceleration. The signs of old spark plugs are highly similar to a dirty air filter.

Clogged Fuel Injectors

Perhaps your spluttering engine is being caused by clogged fuel injectors. In modern cars with their emission-controlled engines, fuel efficiency is much better than with older vehicles. High-pressure injectors are designed to accurately spray a precise amount of fuel into each cylinder at the correct time. Since these injectors are operating in an environment of high temperatures and pressure, it is very easy for them to get clogged up. Plus, the nozzles have minute openings which are likely to get bunged up with carbon, which forms as a result of the combustion process. When less fuel goes through the injectors, this can lead to engine spluttering, as well as rough idling and reduced performance. If this problem has occurred in your vehicle, your mechanic can physically remove the injectors and clean them using powerful solvents and high pressure.

To help keep them cleaner for longer, you could try using premium gasoline, which has a higher concentration of detergents designed to prevent carbon deposit build up in your engine. Alternatively, you could try using a fuel system additive such as Techron to clean the injectors. However, it may be the case that a professional mechanic needs to get involved to solve the issue. Make sure you read our guide on fuel injector cleaners.

Failed Oxygen Sensor

Another common cause of a spluttering car engine is a bad oxygen sensor. An essential feature of your vehicle emission system, it delves into the exhaust system to monitor the oxygen content in the area. It then sends this information to the engine computer, which maintains the air-fuel balance needed for an efficient engine running. Problems can arise when it gets covered in carbon deposits or simply wears out. As a result, it may start sending inaccurate information to the computer. Poor fuel economy or a rough idle are two possible issues which can arise.

If the oxygen sensor has failed, this can end up leading to a trouble code in the engine computer. You can use a OBD2 scanner to determine if an issue has occurred. You should also listen out for a hissing sound, which will direct you to the problem source. Otherwise, you may notice that your ‘check engine’ light has illuminated. If you are unsure, it is worth taking the car into a professional to determine if this is the source of the problem. Alternatively, replacing the oxygen sensor may be something that you can do yourself if you are handy with cars.

Other Possible Causes

If you have a car which has over 100,000 miles on the clock, it is not as easy to trace the issue to one of these common causes. You may well find that you have a more serious problem on your hands. There could be a compression issue which is down to engine wear. A compression test of your engine’s cylinders will verify whether this is the case. Alternatively, there may be other important components which have worn out and failed, which could require major work.

Related Post: Best Compression Testers

engine spluttering

How the Problem is Solved

There are many different possible causes of a spluttering engine, and the above guide gives you a better idea of some of them. If you have a more modern car, your engine computer should give you more information about what is going on. If the cause doesn’t appear obvious and you can’t solve it yourself, take the car into your mechanic and they will perform all the standard checks. This will involve a check of the electronic parts, the valves and sensors, the condition of the hoses, how the spark plugs and wires are looking, and a glance at the air filters. It may be a combination of two or more of these issues.

A spluttering engine is not something that should be ignored, but it is generally an issue which is solvable without too much fuss. Always listen out for any unusual sounds which your car is making and take it in for regular maintenance to reduce the risk of the issue reoccurring.

Sources:

  1. How Car Engines Work – howstuffworks
  2. How to Maintain Your Car Engine for Higher Efficiency – wikiHow

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