2020 Kia Soul Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2020 Kia Soul and How to Restore Smooth Performance

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Reviewed by
Bo Fader
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 2020 Kia Soul 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 2020 Kia Soul 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.

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 2020 Kia Soul?

To effectively diagnose a rough idle in your 2020 Kia Soul, 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 error codes, as these can provide immediate insights into potential issues. Next, inspect the spark plugs for wear or dirt, as these components play a crucial role in engine performance; replacing them can often resolve idle problems. Following this, examine the air filter for clogs that may restrict airflow, and replace it if necessary. It's also important to check the vacuum hoses for any cracks or disconnections, as leaks can significantly impact engine performance. After these initial checks, assess the fuel system, including the fuel filter and injectors, to ensure they are functioning correctly. Cleaning the throttle body is another vital step, as carbon buildup can disrupt airflow and contribute to rough idling. Finally, test the mass airflow sensor, as a malfunctioning sensor can lead to incorrect air measurements, further complicating idle issues. By following this structured diagnostic approach, you can effectively identify and address the causes of rough idle in your vehicle.

What are the common causes of a rough idle in a 2020 Kia Soul?

When diagnosing a rough idle in a 2020 Kia Soul, 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 clogged air filter, which can significantly restrict airflow to the engine, leading to an uneven idle. Additionally, faulty spark plugs are notorious for causing misfires; if they are worn out, they can disrupt the combustion process, resulting in a rough idle. Another potential issue is vacuum leaks, which can disturb the air-fuel mixture necessary for smooth engine operation. Fuel system problems, such as clogged fuel filters or injectors, can also hinder performance and contribute to rough idling. Furthermore, a malfunctioning oxygen sensor can throw off the air-fuel ratio, exacerbating the issue. Lastly, ignition system problems, including faulty ignition coils or distributors, can lead to similar symptoms. By addressing these common causes through regular maintenance and timely repairs, you can effectively resolve the rough idle issue and ensure your Kia Soul runs smoothly.

How urgent is it to address the rough idle in my 2020 Kia Soul?

Addressing a rough idle in your 2020 Kia Soul is crucial for maintaining the vehicle's overall performance and longevity. A rough idle can indicate underlying issues with the engine, such as problems with the fuel or ignition systems, which, if left unresolved, may lead to decreased fuel efficiency and poor driving performance. Moreover, neglecting this symptom can result in more severe engine damage over time, potentially leading to costly repairs that could have been avoided with timely intervention. It is essential to recognize that a rough idle may also signal more serious problems that could escalate if not addressed promptly. Therefore, prioritizing regular maintenance and promptly addressing any irregularities, such as a rough idle, is vital to ensure your Kia Soul operates smoothly and safely, ultimately protecting your investment and enhancing your driving experience.

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