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Audi Engine Misfire

Reasons for Audi Engine Misfires from the Best Louisville Mechanics

Posted on October 16, 2019 by smikyautomowp

Representing some of the best in modern German engineering and innovation, Audi vehicles are thoughtfully designed to handle the challenges and rigours of everyday life without compromising on style. However, even the best-made cars can start to fail without good maintenance standards and practices. This careless behavior can reduce the lifespan of your Audi dramatically, causing frustration behind the wheel. Part of maintaining your Audi is to avoid engine misfires. In this article, we will discuss what causes engine misfires and what to do to prevent them in the future.

The Combustion Process

Unless a specialized design, all vehicles adhere to a four-stroke combustion system to operate. This combustion system operates in a continuous cycle while driving to maintain forward momentum. The four stroke process is as follows:

Intake (Stroke 1)

During the intake stroke, a mixture of air and fuel enters the engine through the inlet valve. This is achieved through the cylinder, piston, and crankshaft of your Audi working together.

Compression (Stroke 2)

The inlet valve closes, which triggers the compression stroke. The piston then moves backwards into the cylinder which increases pressure levels within the chamber. This increases the flammability of the air and fuel in the engine.

Power (Stroke 3)

This is when the ignition of the fuel happens and the combustion begins. The ignition coil provides the spark plugs with the high voltage electricity needed to create the sparks that ignite the fuel in a small explosion of energy. The explosion releases hot gas which causes the piston to drop from the cylinder, allowing the energy created to escape and power the crankshaft, which gives your Audi drive.

Exhaust (Stroke 4)

Now the outlet valve opens and the burned fuel, also known as exhaust gases, can exit the engine and vehicle through the catalytic converter and exhaust pipe.

The cycle then repeats.


The four strokes of the combustion cycle needs to be completed perfectly in order for optimum ignition to be achieved. If there is any failure in these steps, then a misfire will occur, affecting the way your engine operates or preventing combustion from happening entirely. There are three types of misfire:

Lean Misfire: Caused by an off-balance in the air-to-fuel ratio
Ignition Misfire: Caused by a fault in the ignition process, such as the ignition coils or spark plugs

Mechanical Misfire: Caused by any failure of the mechanical systems, such as the pistons

What causes misfires to occur?

In general, many of the common causes of misfire can be prevented through stringent maintenance standards and regular servicing. However, sometimes faults are unavoidable. Listed below are the most common culprits.

Faults in the Fuel Injection System

The fuel injection system can begin to fail simply with age but can also be accelerated with poor maintenance. The most common type of failure in this system are clogs in the injectors, which alters the air/fuel ratio in the engine, increasing the risk of ignition misfires.

Wiring Issues

Deterioration of wiring within your vehicle is natural as your Audi ages. One of the most common electrical parts to fail is the spark plug wiring. As mentioned earlier, if the spark plugs don’t work correctly, then ignition of the fuel will be unreliable, resulting in ignition misfires and stalling. Another electrical part which can also commonly fail and cause ignition issues are the ignition coils, so have the coils checked along with the spark plugs if you suspect an issue.

Improper Crank Position

As previously discussed, the crankshaft plays an important role in the combustion cycle. This part has a sensor to ensure it is in the right potion and rotates at the correct speed, which in turn, regulates the other systems of the engine. If the sensor becomes faulty, it can contribute to mechanical misfires.

Audi Engine Issue Check

St. Matthews Import Service

The dedicated team of experts at St. Matthews Import Service know what it takes to keep your Audi in peak condition. Residents of Louisville, KY can choose from multiple locations for automotive care, including the Hubbards Lane location for automotive service and repair. We have over 45 years of experience, leading many Audi drivers to choose St. Matthews time and time again for all their vehicle’s needs.

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