2018 Mitsubishi Outlander Sport Has Rough Idle

Diagnosing Causes of Rough Idle in Your 2018 Mitsubishi Outlander Sport and How to Resolve Them

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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 2018 Mitsubishi Outlander Sport 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 Mitsubishi Outlander Sport 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 Mitsubishi Outlander Sport?

When faced with a rough idle in your 2018 Mitsubishi Outlander Sport, start by checking the spark plugs, as they play a crucial role in engine performance. Worn or faulty spark plugs can lead to misfires, resulting in an uneven idle. Next, inspect the air filter; a clogged filter can restrict airflow, causing the engine to struggle. If these components are in good condition, turn your attention to the fuel system. Ensure that the fuel injectors, filter, and pump are functioning properly, as any issues here can significantly impact engine performance. Utilizing an OBD-II scanner is also beneficial; it can reveal error codes that point to specific problems affecting the idle. Additionally, examine the throttle body for cleanliness and functionality, as a dirty throttle body can disrupt the air-fuel mixture. Lastly, check for vacuum leaks in hoses and connections, as these can lead to an unstable idle. By systematically addressing these areas, you can effectively diagnose and potentially resolve the rough idle issue in your vehicle.

What are the common causes of a rough idle in a 2018 Mitsubishi Outlander Sport?

When dealing with a rough idle in your 2018 Mitsubishi Outlander Sport, it's essential to consider several common problems that could 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 malfunctioning fuel injectors, can also hinder engine performance and contribute to rough idling. Lastly, a faulty mass airflow sensor can throw off the air-fuel mixture, further exacerbating the issue. By regularly maintaining these components and addressing any signs of wear or malfunction, you can help ensure a smoother idle and overall better performance from your vehicle.

How urgent is it to address the rough idle in my 2018 Mitsubishi Outlander Sport?

Addressing a rough idle in your 2018 Mitsubishi Outlander Sport is crucial and should not be delayed. Ignoring this symptom can lead to serious engine problems, such as misfiring cylinders or faulty sensors, which may escalate into costly repairs if left unchecked. Additionally, a rough idle can significantly reduce your vehicle's fuel efficiency, resulting in higher fuel costs over time. It can also increase emissions, potentially causing your vehicle to fail emissions tests, which not only affects your wallet but also the environment. Furthermore, the discomfort caused by vibrations and inconsistent performance can detract from your driving experience, making each journey less enjoyable. Therefore, it is essential to address a rough idle promptly to ensure your vehicle operates smoothly, efficiently, and safely.

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