2019 Mercedes-Benz GLE400 Has Rough Idle

Address Rough Idle in Your 2019 Mercedes-Benz GLE400 for a Smoother Ride

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Reviewed by
Aisha
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 GLE400 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 GLE400 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 potential causes of a rough idle in a 2019 Mercedes-Benz GLE400, and what diagnostic steps should be taken?

When tackling a rough idle in your 2019 Mercedes-Benz GLE400, it's essential to adopt a systematic diagnostic approach that begins with the most accessible components. Start by inspecting the spark plugs, as worn or faulty plugs can significantly affect engine performance. Next, check the air filter; a clogged filter can restrict airflow, leading to an uneven idle. If these initial checks do not resolve the issue, turn your attention to the fuel system, where a clogged fuel filter or dirty injectors may be the culprit. Additionally, examine the vacuum lines for any leaks that could disrupt the air-fuel mixture. A thorough cleaning of the throttle body is also advisable, as buildup can hinder its function. Don't overlook the importance of engine sensors; using diagnostic tools to assess their performance can reveal faults that contribute to rough idling. Lastly, inspect the exhaust system for blockages, such as a clogged catalytic converter, which can also impact idle quality. By following this structured approach, you can effectively identify and address the underlying causes of a rough idle, ensuring your vehicle runs smoothly. Regular maintenance and timely interventions are key to maintaining optimal engine performance.

What are the common problems that could cause a rough idle in a 2019 Mercedes-Benz GLE400?

When dealing with a rough idle in your 2019 Mercedes-Benz GLE400, it's essential to consider several common problems that could be affecting your vehicle's performance. One of the primary culprits is a dirty or faulty mass airflow sensor, which can disrupt the delicate balance of the air-fuel mixture necessary for smooth engine operation. Additionally, vacuum leaks can create an imbalance in this mixture, leading to erratic idling. Worn or faulty spark plugs are another frequent issue, as they can cause misfires that result in a rough idle. It's also important to check the fuel filter; if it's clogged, it can restrict fuel flow, further impacting engine performance. A malfunctioning oxygen sensor can disrupt the air-fuel ratio, while issues with the Exhaust Gas Recirculation (EGR) valve can also contribute to rough idling. By systematically addressing these potential problems, you can effectively diagnose and resolve the rough idle in your GLE400, ensuring a smoother driving experience.

How urgent is it to address the rough idle in my 2019 Mercedes-Benz GLE400?

Addressing a rough idle in your 2019 Mercedes-Benz GLE400 is not just a matter of comfort; it is crucial for the overall health of your vehicle. A rough idle can indicate serious underlying issues such as faulty spark plugs, fuel system malfunctions, or air intake problems. Ignoring these symptoms can lead to decreased fuel efficiency, engine misfires, and potentially severe damage to engine components, which can result in costly repairs. For DIY enthusiasts, it is essential to recognize that timely maintenance and repairs can prevent more significant problems down the line. If you notice your vehicle idling roughly, it is advisable to conduct a thorough inspection or consult a qualified mechanic to diagnose the root cause. Taking prompt action not only enhances your vehicle's performance but also ensures its longevity, making it a wise investment for any car owner.

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