2018 Lexus LX570 Has Rough Idle

Diagnosing the Causes of Rough Idling in Your 2018 Lexus LX570 and How to Restore Smooth Performance

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Reviewed by
Andrew Hajjar
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 2018 Lexus LX570 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 2018 Lexus LX570 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 initial diagnostic steps to take for a rough idle in a 2018 Lexus LX570?

When addressing a rough idle in your 2018 Lexus LX570, it's essential to adopt a methodical diagnostic approach that begins with the most straightforward checks. Start by using an OBD-II scanner to retrieve any fault codes from the vehicle's computer system, as these codes can highlight specific issues that need attention. Next, inspect the spark plugs for wear or fouling, as these components play a crucial role in engine performance. A clean and functional air filter is also vital; ensure it is free from dirt and blockages that could hinder airflow. Additionally, examine the vacuum hoses for any signs of damage or leaks, as these can disrupt the air-fuel mixture and contribute to idle problems. Testing the mass airflow sensor is another critical step, as a malfunctioning sensor can significantly affect engine performance. Finally, don't overlook the throttle body; check for carbon buildup or dirt that may impede its function. By systematically following these diagnostic steps, you can effectively identify and address the root causes of a rough idle, ensuring your Lexus LX570 runs smoothly.

What are the common problems that could cause a rough idle in a 2018 Lexus LX570?

When dealing with a rough idle in a 2018 Lexus LX570, 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, leading to performance issues. Additionally, faulty spark plugs are notorious for causing misfires, which can manifest as a rough idle. Another potential issue is vacuum leaks; these can disrupt the delicate balance of the air-fuel mixture, resulting in an unstable idle. Fuel system problems, such as a clogged fuel filter or a malfunctioning fuel pump, can also impact engine performance and contribute to rough idling. Furthermore, a malfunctioning Mass Airflow Sensor (MAF) can throw off the air-fuel mixture, exacerbating the problem. Lastly, issues with the Exhaust Gas Recirculation (EGR) valve can interfere with the combustion process, leading to rough idling. By being aware of these common problems, DIYers can take proactive steps to diagnose and address the underlying causes of a rough idle, ensuring their Lexus LX570 runs smoothly. Regular maintenance and timely repairs are key to maintaining optimal vehicle performance.

How urgent is it to address the rough idle in a 2018 Lexus LX570?

Addressing a rough idle in your 2018 Lexus LX570 is crucial for maintaining both safety and performance. A rough idle can indicate underlying engine issues that, if left unresolved, may escalate into more severe problems, potentially leading to engine failure or costly repairs. Ignoring this symptom not only compromises your vehicle's fuel efficiency and overall performance but can also pose safety risks, especially if the engine stalls unexpectedly while driving. Timely intervention through regular maintenance and repairs can prevent these complications, ensuring that your Lexus operates smoothly and reliably. Therefore, it is advisable to prioritize addressing a rough idle promptly to safeguard your vehicle's longevity and your driving experience.

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