2019 Mercedes-Benz AMG GT Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2019 Mercedes-Benz AMG GT 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 Mercedes-Benz AMG GT 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 Mercedes-Benz AMG GT 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.

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.

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 steps to diagnose a rough idle in a 2019 Mercedes-Benz AMG GT?

To effectively diagnose a rough idle in your 2019 Mercedes-Benz AMG GT, it's essential to adopt a systematic diagnostic approach that begins with simpler checks before progressing to more complex assessments. Start by utilizing a diagnostic scanner to identify any fault codes, as these can provide immediate insights into potential issues affecting engine performance. Next, inspect the spark plugs for signs of wear or fouling, since faulty plugs can lead to misfires that contribute to a rough idle. Following this, examine the air filter; a clogged or dirty filter can restrict airflow, which is critical for optimal engine function. It's also important to assess the fuel system, including the fuel filter and injectors, to ensure that fuel delivery is not compromised. Additionally, check the vacuum hoses for any leaks, as these can disrupt the air-fuel mixture and exacerbate idle problems. Inspecting the throttle body for carbon buildup is another key step, as dirt can hinder airflow and affect engine performance. Lastly, verify the functionality of the mass airflow sensor, since a malfunctioning sensor can send incorrect data to the engine control unit, leading to rough idling. By following this structured approach, you can effectively pinpoint and resolve the underlying causes of a rough idle in your vehicle.

What are the common problems that could cause a rough idle in a 2019 Mercedes-Benz AMG GT?

When diagnosing a rough idle in a 2019 Mercedes-Benz AMG GT, it's essential to explore several common problems that may be impacting your vehicle's performance. One significant factor could be dirty or faulty spark plugs, which can lead to misfiring and an uneven idle. Additionally, vacuum leaks in the intake system can disrupt the air-fuel mixture, exacerbating the rough idle issue. A malfunctioning mass airflow sensor is another potential culprit, as it can cause incorrect air/fuel ratios, resulting in poor engine performance. Fuel system issues, such as a clogged fuel filter or a failing fuel pump, can also contribute to rough idling by affecting fuel delivery to the engine. Furthermore, a faulty oxygen sensor may lead to an improper air/fuel mixture, while problems with the Exhaust Gas Recirculation (EGR) valve can impact engine performance at idle. Addressing these issues promptly is crucial for maintaining optimal vehicle performance and preventing further damage, so if you notice a rough idle, consider inspecting these components or consulting a qualified mechanic for a thorough diagnosis.

How urgent is it to address the rough idle in a 2019 Mercedes-Benz AMG GT?

Addressing a rough idle in your 2019 Mercedes-Benz AMG GT is crucial for maintaining the vehicle's performance and preventing further complications. A rough idle can signal underlying engine problems that, if left unchecked, may escalate into more severe issues, leading to costly repairs and decreased fuel efficiency. Moreover, neglecting this symptom can compromise the overall safety and reliability of your vehicle, as it may indicate failing components that could affect engine operation. Regular maintenance and timely intervention are essential to ensure that your AMG GT runs smoothly and efficiently. Therefore, if you notice a rough idle, it is advisable to consult a qualified mechanic who can accurately diagnose the problem and recommend necessary repairs, ultimately safeguarding your investment and enhancing your driving experience.

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