2015 Hyundai Elantra GT Has Rough Idle

Causes of Rough Idling in Your 2015 Hyundai Elantra GT 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 Hyundai Elantra GT 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 2015 Hyundai Elantra GT 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 2015 Hyundai Elantra GT?

To effectively diagnose a rough idle in your 2015 Hyundai Elantra GT, start with the simplest checks before moving on to more complex diagnostics. Begin by inspecting the check engine light; if it’s illuminated, this is a clear indicator that the engine management system has detected a fault. Utilize an OBD-II scanner to retrieve any trouble codes, which will guide you toward specific issues. Next, examine the engine for vacuum leaks, as these are common culprits for rough idling. Following this, inspect the spark plugs and ignition coil, as their condition can significantly impact engine performance. Pay attention to the RPM levels during idle; fluctuations can provide further clues about the underlying problem. Additionally, ensure that the fuel system is operating correctly to maintain the right air-to-fuel ratio, and check the air intake system to confirm that the engine is receiving the proper airflow. By systematically addressing these areas, you can pinpoint the cause of the rough idle and take the necessary steps to resolve it.

What are the common causes of a rough idle in a 2015 Hyundai Elantra GT?

When experiencing a rough idle in your 2015 Hyundai Elantra GT, it's crucial to understand the common problems that could be at play. One of the primary culprits is a vacuum leak, which can disrupt the air-fuel mixture and lead to engine misfires. Additionally, issues with the spark plugs or ignition coil can also contribute to rough idling, as these components are essential for proper combustion. Other potential causes include a clogged air filter, which restricts airflow, and faulty fuel injectors that may not deliver the right amount of fuel to the engine. Identifying these issues early on is vital, as neglecting them can result in more significant mechanical problems and increased repair costs down the line. By being aware of these common causes, DIY enthusiasts can take proactive steps to troubleshoot and address rough idle conditions effectively.

How urgent is it to address the rough idle in my 2015 Hyundai Elantra GT?

Addressing the rough idle in your 2015 Hyundai Elantra GT is crucial for maintaining the vehicle's performance and longevity. A rough idle can signal various underlying problems, such as vacuum leaks or issues with spark plugs and ignition coils, which, if ignored, may lead to more severe complications. Not only can a rough idle decrease fuel efficiency and increase emissions, but it can also result in engine misfires that could escalate into costly repairs. If you notice additional symptoms like a check engine light or difficulty starting your car, it’s essential to act quickly. While it may not seem as urgent as a safety-related issue, neglecting a rough idle can lead to significant engine damage over time. Regular maintenance and prompt repairs are key to ensuring your vehicle runs smoothly, so don’t overlook this seemingly minor issue; addressing it now can save you from more extensive repairs down the road.

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