2019 Audi A5 Quattro Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2019 Audi A5 Quattro and How to Resolve Them

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
21% chance it's the
Spark Plugs
0%
15% chance it's the
Ignition Coil
0%
64% chance it's
Something else
The most common reasons a 2019 Audi A5 Quattro has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
  • Spark Plugs: Worn or fouled spark plugs can lead to misfires, poor fuel economy, and difficulty starting the engine.
  • Ignition Coil: A faulty ignition coil can cause misfires, rough idling, and difficulty starting the engine due to inadequate spark delivery to the spark plugs.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2019 Audi A5 Quattro has rough idle?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Brake caliper failure occurs in two different ways, and they create different symptoms.

The caliper can become stuck, in which case it won't release the brake pads. The seized caliper will cause the vehicle to brake constantly on one side, forcing the car to move toward that side. This pulling will be accompanied by a strong odor from one wheel.

Another way calipers fail is by leaking. If the caliper leaks, the brake pedal will feel too easy to push, and will sink all the way to the floor when held. Braking will become less effective the longer this goes on. There may also be brake fluid leaking onto the wheel.

Here are a few common symptoms of worn-out brake pads:

  1. Low brake pad warning light is on: Not all vehicles are equipped with this system, but if yours is, this dashboard indicator light will likely be the first signal it’s time to replace your brake pads.
  2. Brakes start to squeal regularly: This is often one of the first signs of worn brake pads and is caused by a metallic piece built into brake pads for this exact purpose. This part contacts the brake rotor to make a squealing or whining noise when the pads are low.
  3. Brakes make loud grinding noise: If not addressed early enough, your brake pads may get so worn that the metal backing plate of the pad grinds against the metal rotor.
  4. Brake pads look thin: You may be able to visually check your brake pad thickness to determine if they need replacement.

Brake rotors are mainly maintenance free, but when they have been subjected to abnormally hard use, the heat they absorb can cause the metal to turn blue, and cracking to occur. When this occurs, customers often specify they have lost braking power, or the vehicle's brakes are making noise. There may be no symptoms at all related to changing the brake rotors, since it is recommended to change brake rotors on most modern vehicles when performing a standard brake service.

Most often, a brake system inspection will just be a routine portion of manufacturer specified maintenance, and will be performed at mileage intervals. In those cases, there will likely be no symptoms. However, when a brake system makes a funny noise, causes vibration, is hard to use, will not slow the vehicle, prevents the vehicle from driving, makes the vehicle pull to one side, or leaks brake fluid, the vehicle will need a visit dedicated to the inspection of the brake system.

What are the initial diagnostic steps to take for a rough idle in a 2019 Audi A5 Quattro?

When faced with a rough idle in your 2019 Audi A5 Quattro, the first step is to check for fault codes using a diagnostic scanner. This tool can reveal any underlying issues that may be affecting engine performance. Next, inspect the air intake system for leaks or clogs, as these can disrupt airflow and lead to an unstable idle. A clean and properly installed air filter is crucial for optimal engine function. Following this, evaluate the fuel system by examining components like the fuel filter and injectors to ensure they are delivering fuel effectively. Additionally, inspect the spark plugs for signs of wear or fouling, as faulty plugs can cause misfires that contribute to rough idling. Don’t forget to check the Positive Crankcase Ventilation (PCV) system, as a malfunction here can also impact engine performance. Lastly, look for any vacuum leaks in hoses and connections, as these can disrupt the air-fuel mixture. By systematically following these diagnostic steps, you can effectively identify and address the causes of a rough idle in your Audi A5 Quattro.

What are the common problems that could cause a rough idle in a 2019 Audi A5 Quattro?

When dealing with a rough idle in a 2019 Audi A5 Quattro, it's essential to consider several common problems that could be at play. One of the primary culprits is a dirty or faulty mass airflow sensor, which can disrupt the delicate balance of the air-fuel mixture, leading to an uneven idle. Additionally, vacuum leaks in the intake system can introduce unmetered air, further complicating the engine's performance. Worn-out spark plugs or faulty ignition coils are also significant factors, as they can cause misfires that manifest as a rough idle. Another potential issue is a clogged fuel filter, which restricts fuel flow and can severely impact engine performance. Problems with the Exhaust Gas Recirculation (EGR) valve may also contribute to idle irregularities, as can a malfunctioning throttle body that disrupts air intake. Lastly, a dirty or faulty oxygen sensor can throw off the air-fuel mixture, exacerbating the rough idle. By systematically checking these components, DIYers can effectively troubleshoot and resolve the rough idle issue, restoring the smooth operation of their Audi A5 Quattro.

How urgent is it to address the rough idle in my 2019 Audi A5 Quattro?

Addressing the rough idle in your 2019 Audi A5 Quattro is crucial for maintaining both the performance and safety of your vehicle. A rough idle often indicates underlying engine problems, such as faulty spark plugs, fuel system malfunctions, or issues with the air intake. If left unaddressed, these symptoms can escalate, leading to decreased fuel efficiency, engine misfires, and even significant damage to engine components. The urgency of resolving a rough idle cannot be overstated, as neglecting it may result in costly repairs and a compromised driving experience. Regular maintenance and timely inspections by a qualified mechanic are essential to diagnose and rectify the root cause of the issue, ensuring your Audi A5 Quattro continues to operate smoothly and efficiently. Prioritizing this repair not only enhances your vehicle's longevity but also safeguards your safety on the road.

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