2015 Mitsubishi Mirage Has Rough Idle

Common Causes of Rough Idling in Your 2015 Mitsubishi Mirage and How to Resolve Them

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Reviewed by
Devin Cabugcal
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 2015 Mitsubishi Mirage 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 2015 Mitsubishi Mirage 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.

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.

What are the steps to diagnose a rough idle in a 2015 Mitsubishi Mirage?

To effectively diagnose a rough idle in your 2015 Mitsubishi Mirage, start with a systematic approach that prioritizes simpler checks before moving on to more complex diagnostics. Begin by using an OBD-II scanner to check for any fault codes, as these can quickly point you to specific issues within the engine control module. Next, inspect the spark plugs for wear or fouling, as these components are crucial for proper combustion and can significantly impact idle quality. Following this, examine the air filter; a clogged filter can restrict airflow, leading to performance issues. Don’t overlook the vacuum hoses, as any cracks or disconnections can create leaks that disrupt engine performance. After these initial checks, test the mass airflow sensor, which is vital for measuring air intake; a malfunction here can also cause rough idling. Additionally, inspect the fuel system for potential problems like clogged injectors or a failing fuel pump, as these can directly affect engine performance. Finally, take a look at the throttle body; cleaning or replacing it may be necessary if it’s dirty or malfunctioning. By following this structured diagnostic approach, you can effectively identify and resolve the causes of a rough idle in your vehicle.

What are the common causes of a rough idle in a 2015 Mitsubishi Mirage?

When diagnosing a rough idle in your 2015 Mitsubishi Mirage, it's crucial to consider several 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, resulting in an uneven idle. Additionally, faulty spark plugs are notorious for causing misfires; if they are worn out, they can lead to a rough running engine. Another potential issue is vacuum leaks, which can disrupt the delicate air-fuel mixture necessary for smooth operation. Fuel system problems, such as clogged fuel filters or injectors, can also hinder performance and contribute to a rough idle. Furthermore, a malfunctioning mass airflow sensor (MAF) can throw off the air-fuel balance, exacerbating idle issues. Lastly, the idle air control valve (IAC) plays a critical role in maintaining the engine's idle speed, and if it fails, it can lead to significant fluctuations in engine performance. Addressing these issues promptly will help restore your vehicle's optimal performance and ensure a smoother driving experience.

How urgent is it to address the rough idle in a 2015 Mitsubishi Mirage?

Addressing a rough idle in your 2015 Mitsubishi Mirage should be treated as a priority due to the potential risks and complications that can arise from neglecting this symptom. A rough idle often signals underlying issues with the engine or related components, which can escalate if not promptly addressed. Ignoring this problem may lead to decreased fuel efficiency, increased emissions, and even more severe engine damage over time. Additionally, components such as spark plugs, fuel injectors, or sensors may be malfunctioning, which are critical for the vehicle's performance and safety. By taking immediate action to diagnose and resolve the rough idle, you not only enhance the driving experience but also safeguard against costly repairs in the future. Regular maintenance and timely interventions are key to ensuring the longevity and reliability of your vehicle, making it essential to prioritize any signs of a rough idle.

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