2021 Mercedes-Benz AMG GT 53 Has Rough Idle

Resolve Rough Idle in 2021 Mercedes-Benz AMG GT 53 for a Smoother Ride

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Reviewed by
Bo Fader
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 2021 Mercedes-Benz AMG GT 53 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 2021 Mercedes-Benz AMG GT 53 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 2021 Mercedes-Benz AMG GT 53?

When faced with a rough idle in your 2021 Mercedes-Benz AMG GT 53, the first step is to check for error codes using a diagnostic scanner. This tool can reveal any stored codes in the vehicle's computer system, offering crucial insights into potential problems. Next, inspect the spark plugs to ensure they are in good condition and properly gapped, as worn or fouled plugs can significantly affect engine performance. Following this, evaluate the air intake system for any leaks or clogs, as a compromised intake can disrupt the air-fuel mixture, leading to idling issues. Additionally, examine the fuel system components, including the fuel filter and injectors, since a clogged filter or malfunctioning injectors can also contribute to a rough idle. Don’t forget to inspect the vacuum hoses for any cracks or leaks, as these can adversely affect engine performance. Finally, test the mass airflow sensor to ensure it is functioning correctly, as a faulty sensor can disrupt air intake measurements. By systematically following these diagnostic steps, you can effectively identify and address the causes of a rough idle in your vehicle.

What are the common causes of a rough idle in a 2021 Mercedes-Benz AMG GT 53?

When dealing with a rough idle in your 2021 Mercedes-Benz AMG GT 53, it's crucial to understand the common problems that may be at play. One of the primary culprits is a dirty or clogged air filter, which can significantly restrict airflow to the engine, resulting in an uneven idle. Additionally, faulty spark plugs are notorious for causing misfires; if they are worn out, they can lead to a rough running engine. Another issue to consider is vacuum leaks, which can disrupt the delicate air-fuel mixture necessary for smooth operation. Fuel system problems, such as clogged fuel filters or injectors, can also hinder engine performance and contribute to a rough idle. Furthermore, ignition system issues, including failing ignition coils, can prevent the engine from maintaining a steady idle. Lastly, malfunctioning engine sensors, like the mass airflow or oxygen sensors, can cause the engine to run poorly at idle. By identifying and addressing these common problems, DIY enthusiasts can take significant steps toward restoring their vehicle's performance.

How urgent is it to address the rough idle in a 2021 Mercedes-Benz AMG GT 53?

Addressing a rough idle in your 2021 Mercedes-Benz AMG GT 53 is not just a matter of comfort; it is crucial for the longevity and performance of your vehicle. A rough idle can indicate serious underlying problems, such as issues with the fuel system, ignition components, or even engine management systems. If left unaddressed, these problems can escalate, leading to more severe engine damage and costly repairs. Additionally, a rough idle often correlates with decreased fuel efficiency, which can significantly impact your driving experience and wallet. By tackling this issue promptly, you not only enhance your vehicle's performance but also safeguard against potential safety risks associated with engine malfunctions. Therefore, if you notice your AMG GT 53 idling roughly, it is imperative to investigate and resolve the issue as soon as possible to maintain optimal performance and prevent further complications.

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2021 Mercedes-Benz AMG GT 53 Rough Idle Issues & Repairs