2012 Buick Verano Has Rough Idle

Diagnosing Causes of Rough Idle in Your 2012 Buick Verano and How to Restore Smooth Performance

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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 2012 Buick Verano 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 2012 Buick Verano 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 initial diagnostic steps to take for a rough idle in a 2012 Buick Verano?

When faced with a rough idle in your 2012 Buick Verano, it's essential to adopt a systematic diagnostic approach to identify the root cause effectively. Start by utilizing an OBD-II scanner to check for any fault codes, as these can provide immediate insights into potential issues. Next, inspect the spark plugs for wear or fouling, as these components are critical for proper engine performance; replacing damaged plugs can often resolve misfires that lead to rough idling. Following this, examine the air intake system, including the air filter and throttle body, for any obstructions that could hinder airflow. It's also crucial to check for vacuum leaks by visually inspecting hoses and connections, as these leaks can disrupt the air-fuel mixture. Additionally, assess the fuel system by looking at the fuel filter and injectors to ensure they are delivering fuel efficiently. Finally, evaluate the idle control valve to confirm it is functioning correctly, as a malfunction here can significantly affect idle stability. By methodically working through these steps, you can effectively diagnose and address the rough idle issue in your vehicle.

What are the common causes of a rough idle in a 2012 Buick Verano?

When diagnosing a rough idle in your 2012 Buick Verano, it's essential to consider several common issues that could be affecting your vehicle's performance. One of the primary culprits is a vacuum leak, which can disrupt the engine's air-to-fuel ratio, leading to an unstable idle. Additionally, worn or faulty spark plugs can hinder efficient combustion, resulting in a rough idle as well. Another potential issue is a malfunctioning ignition coil, which may cause engine hesitation and misfires, further contributing to the roughness. Changes in air intake can also play a significant role; if the amount of air entering the engine fluctuates, it can impact how smoothly the engine idles. Lastly, irregular ignition can lead to inconsistent engine performance, making it crucial to check these components if you're experiencing a rough idle. By addressing these common problems, you can restore your Buick Verano's smooth operation and enhance your driving experience.

How urgent is it to address the rough idle in my 2012 Buick Verano?

Addressing a rough idle in your 2012 Buick Verano is not just a matter of comfort; it is crucial for the vehicle's overall health and performance. Ignoring this symptom can lead to a cascade of problems, including decreased fuel efficiency and potential damage to critical engine components. A rough idle often indicates underlying issues such as vacuum leaks, faulty spark plugs, or ignition coil malfunctions, which, if left unresolved, can escalate into more severe mechanical failures. The longer you wait to diagnose and fix the problem, the more likely you are to face costly repairs down the line. Moreover, a rough idle can compromise your vehicle's performance, making it less reliable and potentially unsafe to drive. Therefore, it is essential to take immediate action to identify the cause of the rough idle and implement the necessary repairs, ensuring your Buick Verano runs smoothly and efficiently for years to come.

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2012 Buick Verano Rough Idle: Causes & Repair Costs