Mitsubishi Outlander Has Rough Idle

Diagnosing Causes of Rough Idle in Your Mitsubishi Outlander and How to Resolve the Issue

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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 Mitsubishi Outlander 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 Mitsubishi Outlander 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.

Customers with drum brake systems often specify they have lost braking power, or that the vehicle's brakes are making noise. This is because brake drums do not dissipate heat very well, so the heat from hard braking will cause stress fractures. These fractures make can make noise on the brake shoes as the drum revolves around the shoes. Lastly, the brake shoes may not be problematic, but may cause a grinding noise while stopping. This would indicate the shoes have no braking material left, and the brake shoes must be changed before the vehicle can be safely driven.

Learn more about brake shoe symptoms

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.

Troubleshooting Rough Idle in a Mitsubishi Outlander

When troubleshooting rough idle in a Mitsubishi Outlander, it's essential to adopt a systematic diagnostic approach. Begin by checking the spark plugs, as worn or dirty plugs are often the simplest culprits behind rough idling. If the spark plugs appear to be in good condition, move on to inspect the air filter; a clogged filter can significantly restrict airflow, leading to performance issues. Next, examine the fuel system, focusing on the fuel filter and injectors, as blockages here can disrupt fuel delivery. If these components are functioning well, investigate for vacuum leaks, which can alter the air-fuel mixture and cause instability in idling. Additionally, assess the idle air control valve and throttle body, as both play critical roles in maintaining a steady idle. Finally, check the engine sensors, including the mass airflow and oxygen sensors, to ensure they are operating correctly. By following this methodical approach, you can effectively identify and resolve the underlying issues causing rough idle in your Mitsubishi Outlander.

Troubleshooting Rough Idle in a Mitsubishi Outlander

When dealing with a rough idle in your Mitsubishi Outlander, it's crucial to understand the common problems that may be at play. One of the primary culprits is vacuum leaks, which can disrupt the air-fuel mixture and lead to poor engine performance. Inspecting hoses and connections for any signs of wear or damage can help identify these leaks. Additionally, spark plug issues are another frequent cause; worn or faulty spark plugs can hinder the combustion process, resulting in a rough idle. Regularly checking and replacing spark plugs as needed can significantly improve engine smoothness. Ignition coil problems can also contribute to rough idling, as a malfunctioning coil may fail to deliver the necessary spark to the plugs. Furthermore, a clogged catalytic converter can restrict exhaust flow, causing the engine to run poorly. It's also important to examine the mass airflow sensor, as a faulty sensor can affect the air-fuel mixture, leading to rough idling. Lastly, be aware of a rich air-fuel mixture and potential ignition misfires, which can manifest through diagnostic trouble codes. By systematically addressing these common issues, you can enhance the performance and efficiency of your Mitsubishi Outlander, ensuring a smoother driving experience.

Why is a Mitsubishi Outlander Idling Rough and What Should You Do?

When your Mitsubishi Outlander is idling rough, it’s crucial to address the issue without delay. Ignoring symptoms like shaking or stalling can lead to significant engine damage, increased repair costs, and even safety hazards while driving. Common causes such as vacuum leaks, worn spark plugs, or faulty ignition coils can disrupt the engine's performance, leading to misfires and poor acceleration. If left unresolved, these problems can escalate, potentially resulting in a breakdown or more extensive engine repairs. Regular maintenance, including checking for vacuum leaks and ensuring that spark plugs and ignition components are in good condition, is essential for preventing rough idle and maintaining your vehicle's overall health. By taking immediate action, you not only enhance your driving experience but also safeguard your investment in the vehicle.

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