2016 Hyundai Sonata Has Rough Idle

Common Causes of Rough Idling in Your 2016 Hyundai Sonata 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 2016 Hyundai Sonata has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
  • Spark Plugs: A worn or fouled spark plug can cause misfires, rough idling, and decreased fuel efficiency due to incomplete combustion.
  • 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 2016 Hyundai Sonata 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 steps to diagnose a rough idle in a 2016 Hyundai Sonata?

To diagnose a rough idle in your 2016 Hyundai Sonata, begin with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by connecting an OBD-II scanner to check for any trouble codes, as these can provide immediate insights into potential issues. If no codes are present, inspect the vacuum lines for leaks, as even small cracks can disrupt engine performance. Next, clean the throttle body and Mass Airflow Sensor (MAF), as dirt buildup can hinder airflow and fuel delivery, leading to rough idling. Don’t overlook the spark plugs; inspect them for wear or fouling, as they are crucial for proper combustion. Additionally, examine the ignition coil, since a malfunction here can significantly affect engine smoothness. Lastly, consider the EGR switching valve, which can also contribute to idle issues if faulty. By following this structured diagnostic approach, you can effectively identify and address the root cause of the rough idle in your Sonata, ensuring a smoother driving experience.

What are the common causes of a rough idle in a 2016 Hyundai Sonata?

When dealing with a rough idle in your 2016 Hyundai Sonata, it's essential to understand the common problems that could be causing this frustrating issue. One of the primary culprits is vacuum leaks, which can disrupt the air-fuel mixture and lead to an unstable idle. Inspecting the vacuum lines for any cracks or disconnections can be a good starting point. Additionally, faulty spark plugs are notorious for causing rough idling; if they are worn or damaged, replacing them can significantly improve engine performance. The ignition system also plays a crucial role, so checking the ignition coils and other components for faults is advisable. Engine misfires, often resulting from issues in the ignition system or fuel delivery, can lead to a rough idle and should be diagnosed promptly. Lastly, don't overlook the condition of your motor mounts, as worn mounts can cause excessive vibration at idle, contributing to the roughness. By systematically checking these areas, you can identify and resolve the underlying issues affecting your Sonata's idle quality.

How urgent is it to address the rough idle issue in my 2016 Hyundai Sonata?

Addressing the rough idle issue in your 2016 Hyundai Sonata should be considered a priority, as neglecting it can lead to more severe problems down the line. A rough idle often signals underlying issues such as a malfunctioning throttle body, vacuum leaks, or problems with spark plugs and ignition coils. If left unchecked, these issues can escalate, resulting in inconsistent vehicle performance and potentially higher repair costs. Moreover, a rough idle can affect your driving experience, making it less enjoyable and more challenging to control your vehicle. While it may not seem like an immediate emergency, timely intervention is crucial to prevent further complications that could compromise the safety and reliability of your Sonata. For those inclined to tackle this issue themselves, diagnosing the root cause early on can save time and money, ensuring your vehicle remains in optimal condition.

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