2013 Mercedes-Benz GL550 Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2013 Mercedes-Benz GL550 and How to Resolve Them

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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 2013 Mercedes-Benz GL550 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 2013 Mercedes-Benz GL550 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 2013 Mercedes-Benz GL550?

To effectively diagnose a rough idle in your 2013 Mercedes-Benz GL550, it's essential to adopt a methodical approach that begins with simpler checks before progressing to more complex diagnostics. Start by utilizing a diagnostic scanner to retrieve any fault codes from the vehicle's computer system, as these codes can provide immediate insights into potential issues. Next, inspect the spark plugs for signs of wear or fouling, since these components are vital for optimal engine performance. Ensure that the air filter is clean and unobstructed, as a clogged filter can restrict airflow and contribute to a rough idle. Following this, examine the fuel system, focusing on the fuel filter and injectors to ensure proper fuel delivery. It's also crucial to check the vacuum hoses for any damage or disconnections, as these can lead to vacuum leaks that disrupt the air-fuel mixture. Lastly, inspect the throttle body for carbon buildup and verify that the throttle position sensor is functioning correctly. By following this structured diagnostic process, you can effectively pinpoint and address the root causes of a rough idle in your GL550, ensuring smoother engine performance.

What are the common causes of a rough idle in a 2013 Mercedes-Benz GL550?

When diagnosing a rough idle in a 2013 Mercedes-Benz GL550, it's essential to explore several common problems that could be contributing to the issue. One significant factor is the condition of the spark plugs; if they are dirty or worn out, they can cause misfires, leading to an uneven idle. Additionally, a clogged fuel filter can impede fuel flow to the engine, further intensifying the roughness of the idle. Vacuum leaks are another critical concern, as they can disrupt the air-fuel mixture necessary for optimal engine performance. The mass airflow sensor (MAF) is also vital; a malfunction here can alter the air-fuel ratio, resulting in a rough idle. Lastly, the idle air control valve (IAC) is crucial for maintaining a stable idle speed, and any issues with this component can lead to fluctuations in engine performance. By addressing these potential causes promptly, you can help ensure the smooth operation of your Mercedes-Benz GL550.

How urgent is it to address the rough idle issue in my 2013 Mercedes-Benz GL550?

Addressing the rough idle issue in your 2013 Mercedes-Benz GL550 is not just a matter of convenience; it is crucial for the longevity and performance of your vehicle. Ignoring this symptom can lead to significant engine damage, resulting in costly repairs that could have been avoided with timely intervention. Additionally, a rough idle can severely impact your fuel efficiency, leading to increased fuel costs over time. This issue can also affect your vehicle's emissions, potentially causing it to fail emissions tests and contribute to environmental pollution. Furthermore, a rough idle detracts from your driving comfort, making your overall experience less enjoyable. Therefore, it is essential to prioritize resolving this issue to maintain your vehicle's performance, ensure safety, and enhance your driving experience.

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2013 Mercedes-Benz GL550 Rough Idle: Causes & Repairs