2023 Kia K5 Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2023 Kia K5 and How to Restore Smooth Performance

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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 2023 Kia K5 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 2023 Kia K5 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 initial diagnostic steps to take for a rough idle in a 2023 Kia K5?

When faced with a rough idle in your 2023 Kia K5, start by checking the spark plugs, as they are often the simplest and most common culprits. Worn or damaged spark plugs can lead to misfires, resulting in an uneven idle. Next, inspect the air filter; a clogged filter can restrict airflow, affecting the air-fuel mixture and causing rough idling. Following this, examine the fuel system components, including the fuel injectors and fuel filter, to ensure they are functioning properly, as any blockage or malfunction can disrupt engine performance. Utilizing an OBD-II scanner to check for error codes can provide valuable insights into specific issues that may be affecting your vehicle. Additionally, inspect the PCV valve, as a faulty valve can lead to improper ventilation and contribute to idle problems. Don’t forget to check for vacuum leaks in hoses and connections, as these can significantly impact the air intake system. Finally, cleaning the throttle body can help restore proper airflow and improve idle quality. By systematically addressing these areas, you can effectively diagnose and resolve the rough idle issue in your Kia K5.

What are the common problems that could cause a rough idle in a 2023 Kia K5?

When diagnosing a rough idle in your 2023 Kia K5, it's crucial 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, which can also contribute to a rough idle. Another potential issue is vacuum leaks; these can disrupt the delicate balance of the air-fuel mixture, resulting in instability during idling. Fuel system problems, such as clogged fuel filters or malfunctioning fuel injectors, can further exacerbate the situation by hindering proper fuel delivery. Moreover, a faulty mass airflow sensor can miscalculate the air entering the engine, throwing off the air-fuel ratio and causing rough idling. Lastly, issues with the Exhaust Gas Recirculation (EGR) valve can interfere with the combustion process, leading to an inconsistent idle. Addressing these issues promptly is essential for maintaining the optimal performance of your Kia K5 and ensuring a smooth driving experience.

How urgent is it to address the rough idle in a 2023 Kia K5?

Addressing a rough idle in your 2023 Kia K5 should be treated as a priority due to the potential risks and complications that can arise from ignoring this symptom. A rough idle often signals underlying engine problems that, if left unresolved, can escalate into more severe issues, leading to costly repairs and decreased vehicle performance. Additionally, neglecting this issue can result in diminished fuel efficiency, which not only impacts your wallet but also contributes to increased emissions. More critically, a rough idle may indicate serious safety concerns that could compromise your driving experience and put you and others at risk on the road. By prioritizing timely maintenance and repairs, you can ensure the longevity of your vehicle, maintain optimal performance, and safeguard your safety, making it essential to address any signs of a rough idle without delay.

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