What are the Signs of Engine Misfire? | Causes of Engine Misfire

What is an Engine Misfire?

Engine misfire occurs when one or more cylinders of the engine are not producing power. The engine misfiring is a sign of a faulty engine part. The engine misfire due to different causes such as a bad air filter, clogged fuel filter, engine overheating, or a faulty fuel filter.

As you observe the signs of the engine misfire, immediately contact the mechanic to fix the problem. As the engine misfire, you will see a reduction in the fuel economy or reduction in engine power.  

Symptoms of Car Engine Misfire

The common symptoms of car engine misfiring are given below:

1) Rough Acceleration

The rough acceleration is one of the main signs of the car engine misfire. In case of engine misfiring, your engine starts slight or strong vibrations.

You can easily identify the misfire situation in low speed, high gear, and the accelerator to the floor. The rough acceleration is a common symptom of engine misfiring.

2) Rough Idling

In some cases, the engine misfires even when idling. The rough idling occurs when the ECU gets the wrong reading and doesn’t properly mix the air/fuel mixture. As a result, the idling condition becomes very jerky due to that engine may jump upward and downward, and the engine may stall at idle.

The vehicle engine starts idling even on small air-fuel mixture issue. In such condition, you can easily notice misfire.

3) Vibration

All the parts of the car engine are installed in a proper alignment. The engine balancing plays a big role in the efficient working of the vehicle. Therefore, all the engines are well balanced. The engine also contains a balancer shaft and various tricks to reduce vibration as much as possible.

If one or more cylinders are not working properly, the engine may be out of balance which may lead to extreme vibration when accelerating or idling.

4) Check Engine Light

The latest vehicles monitor the various engine sensors through different methods. As the sensor goes bad, or when a sensor detects an engine problem, the sensor sends information to the ECU.

After receiving the data, the engine control unit will determine the severity level of the problem. If the problem occurs multiple times, the ECU will turn on the check engine light to let you know about the problem and allow for repairs.

As the engine control unit detects engine misfiring issues, it sends signal to the check engine light which starts illuminating and also stores the trouble code in the cylinder with the engine misfire. Use the diagnostic scanner to check the trouble code.

5) Abnormal Sounds

When there is a misfire, the engine makes a sudden noise. This sudden noise is known as the backfiring, sneezing or popping.  

The backfiring takes place when unburned fuel leaves a cylinder on the exhaust stroke and then further starts to ignite in the system by sparks from the next cylinder.

When one of the cylinders don’t work at all, the overall sound of the engine may change. The latest four-cylinder vehicle has only three working cylinders.

6) Excessive Exhaust Smoke

Sweet-smelling, black, bluish, or very white exhaust fumes indicate that there is something wrong with your vahicle engine. Dark jet-black exhaust fumes may represent a rich or carbon accumulation. Blue exhaust indicates the oil is burning.

Sweet white exhaust may indicate a head gasket leak. Anything other than air or gasoline in the combustion chamber can damage the ability of the car to burn the air/fuel mixture according to the requirements.

Causes of an Engine Misfire

1) Bad Ignition Coil/Distributor

The ignition coil is one of the most common causes of engine misfire.  Few cars contain a separate ignition coil for each spark plug, while others contain a separate ignition coil with a sparking wire for each spark plug.

The old vehicles contain a distributor as well as ignition coil. If your vehicle contains a separate plug, disconnect each coil and see if one of the cylinders isn’t responding.

As you find the defective ignition coil, then immediately replace it.  

2) Bad Spark Plug

The bad spark plug is also a reason of engine misfiring. Spark plug ensures the proper ignition of the air-fuel mixture. It is responsible to ignite the mixture.

As the spark plug fires the cylinder, the combustion process starts inside the cylinder. Spark plugs usually have low costs. They have an easy maintenance and replacement.

You must properly maintain and replace your spark plug. The proper maintenance of the spark plug will prevent your engine from misfiring.

3) Intake Manifold Gasket Leaks

The inlet leak near the cylinder head is a common issue when it comes to spark plug. This a most common issue in older vehicles that do not have steel air intake gaskets.

Therefore, you must regularly check the older engine of your vehicle. If your vehicle engine is new and its creating misfire issues, you should look at other symptoms of leaks around the inlet.

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