2021 Genesis G70 Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2021 Genesis G70 and How to Resolve Them

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Reviewed by
Andrew Hajjar
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 2021 Genesis G70 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 2021 Genesis G70 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 the rough idle in a 2021 Genesis G70?

To effectively diagnose a rough idle in your 2021 Genesis G70, 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 fouling, as they play a crucial role in engine performance. A clean air filter is essential for optimal airflow, so examine it for dirt or clogs and replace it if necessary. Following this, check the vacuum hoses for any damage or disconnections, as leaks can significantly impact idle quality. Assess the fuel system for clogs or pump issues, ensuring that fuel delivery is consistent. The throttle body should also be inspected for cleanliness and functionality, as a dirty throttle can disrupt idle. Finally, test the mass airflow sensor and check for any vacuum leaks in the intake system, as these can alter the air-fuel mixture and contribute to rough idling. By following this structured diagnostic approach, you can effectively identify and address the underlying causes of rough idle in your vehicle.

What are the common causes of a rough idle in a 2021 Genesis G70?

When dealing with a rough idle in your 2021 Genesis G70, it's crucial to understand the common problems that may be at play. One of the first areas to check is the air filter; a dirty or clogged air filter can significantly restrict airflow to the engine, resulting in an uneven idle. Additionally, inspect the spark plugs, as worn or faulty plugs can cause misfiring, which directly affects engine performance. Another potential culprit is vacuum leaks, which can disrupt the air-fuel mixture and lead to instability in idling. Fuel system issues, such as clogged fuel filters or injectors, can also hinder engine performance, contributing to a rough idle. Furthermore, a malfunctioning Mass Airflow Sensor (MAF) can throw off the air-fuel balance, while problems with the Exhaust Gas Recirculation (EGR) valve can interfere with the combustion process, exacerbating the rough idle. By systematically checking these components, you can identify and address the underlying issues, ensuring your Genesis G70 runs smoothly.

How urgent is it to address the rough idle in a 2021 Genesis G70?

Addressing a rough idle in your 2021 Genesis G70 should be treated with a sense of urgency, as it can indicate underlying engine problems that may escalate if left unattended. A rough idle not only affects the vehicle's performance but can also lead to decreased fuel efficiency and increased wear on engine components. Common culprits such as dirty fuel injectors, malfunctioning oxygen sensors, or faulty spark plugs can exacerbate the issue, potentially resulting in costly repairs down the line. Moreover, neglecting these symptoms could compromise your vehicle's safety and reliability, making it crucial to diagnose and resolve the problem promptly. By prioritizing maintenance and repairs, you can ensure the longevity of your Genesis G70 and avoid more serious issues in the future.

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Fixing Rough Idle Issues in 2021 Genesis G70 | RepairPal