What is an engine misfire?

A properly functioning vehicle is a result of multiple, closely-held components that work efficiently, and in harmony. Any flaw in the operation of these units can tip the balance towards problems that hamper the performance of the car apparatus. An engine misfire is a perfect example of an issue that arises due to the faulty operation of one or more components in a smoothly running system.

What is Engine Misfire?

How does an engine work?

To understand the concept of a misfiring engine, it is imperative to understand its normal operations. Most modern cars run on a precise 4-stroke combustion cycle happening in closed cylinders called 'pistons.' The 4 strokes are:

  1. Intake- Upward movement of pistons to let the air and gas inside the cylinder.
  2. Compression- The air and gas mixture is compressed into a smaller space.
  3. Combustion- Ignition, and explosion of compressed gases to push the piston out producing a burst of power.
  4. Exhaust- Expulsion of waste gases produced as a result of the explosion.

It is a repetition of these strokes that results in power generation due to the combustion of compressed gases. This power is then transferred to the tires and moves the car.

How does an engine misfire?

The functioning of a car engine is a perfectly timed series of operations, and any interference in that order or timing can result in a misfire. Although the car may not come to an absolute halt due to a misfire, it might cause a sudden jerking movement, a loud noise, a smell of gas, or black smoke from the tailpipe. An engine misfire is indicated by a blinking check engine light and increases the fuel consumption of the vehicle resulting in reduced fuel economy.

Why does an engine misfire?

Faults that can elicit misfiring include defects in the functioning of ignition system components, fuel system problems, and mechanical wear and tear of the engine parts.

Ignition system issues can be due to faulty spark plugs, worn ignition coils, defective coil, or a malfunctioning rotor.

The fuel system can cause misfiring resulting from the faulty fuel pump, an obstructed fuel filter, or a broken vacuum hose.

Mechanical causes that can result in misfiring include worn out piston rings, broken valves, faulty timing belt, or defective cylinder walls.

Signs of an engine misfire

Although it is difficult to pinpoint the exact cause of a misfiring engine without help from an auto repair mechanic, some signs can be apparent that should alert the driver about underlying engine faults. These include:

  • Lit up check-engine light
  • Bumpy driving
  • Smell of gas or oil leaks
  • Rough idle
  • Poor engine performance
  • Jerky or sluggish acceleration
  • Unusual sound or exhaust fumes


Engine misfire can cause irreparable damage to the engine and its parts if ignored for too long. It is important to consult an auto repair shop to get a thorough assessment. If you need engine repair services, we invite you to bring your vehicle to our service center today!

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