2008 Acura RL Has Rough Idle

Diagnosing Causes of Rough Idle in Your 2008 Acura RL and Solutions for a Smoother Ride

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Reviewed by
Bo Fader
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 2008 Acura RL 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 2008 Acura RL 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 2008 Acura RL?

When diagnosing a rough idle in your 2008 Acura RL, it's crucial to follow a structured approach that prioritizes simpler checks before delving into more complex issues. Begin by inspecting for vacuum leaks, as these are common culprits that can disrupt engine performance. Next, evaluate the engine's idle speed; erratic fluctuations or stalling can indicate deeper mechanical problems. Pay close attention to any shaking or vibrations while the vehicle is stationary, as these symptoms may reveal underlying issues. Additionally, consider the vehicle's behavior when in gear and at a stop, which can help narrow down specific malfunctions. Don't forget to examine the ignition system; faulty spark plugs can lead to misfiring, while a dirty air filter can significantly impact engine efficiency. Ensure that the oxygen sensors are functioning properly, as they are essential for maintaining the correct air/fuel mixture. Lastly, inspect the fuel injection system for any irregularities that could affect fuel delivery. By systematically checking these components, you can effectively identify and resolve the root cause of the rough idle in your Acura RL, ensuring smoother operation and improved performance.

What are the common causes of a rough idle in a 2008 Acura RL?

When dealing with a rough idle in a 2008 Acura RL, it's essential to consider several common problems that could be affecting your vehicle's performance. One of the primary suspects is a vacuum leak, which can disrupt the air-fuel mixture and lead to an unstable idle. Additionally, worn or faulty spark plugs can cause misfires, resulting in a rough running engine. The ignition coil is another critical component; if it’s malfunctioning, it can lead to poor ignition and contribute to the rough idle. Furthermore, the idle air control system, which regulates the engine's idle speed, may be malfunctioning, causing erratic idling behavior. Lastly, a bad throttle body can restrict airflow, leading to poor engine performance and a rough idle. By systematically checking these components, DIYers can effectively diagnose and potentially resolve the rough idle issue in their Acura RL.

How urgent is it to address the rough idle in my 2008 Acura RL?

Addressing a rough idle in your 2008 Acura RL should be treated with a sense of urgency, as it can indicate underlying issues that, if left unresolved, may lead to significant engine damage and safety risks. Symptoms such as a rough idle often stem from problems like faulty spark plugs, clogged fuel injectors, or malfunctioning oxygen sensors, which can not only decrease fuel efficiency but also compromise the overall performance of your vehicle. Ignoring these signs can escalate into more severe complications, including engine misfires or stalling, which could ultimately result in complete engine failure. By prioritizing timely repairs and regular maintenance, you can prevent costly repairs and ensure the longevity of your vehicle. Therefore, while it may not seem like an immediate emergency, addressing a rough idle promptly is crucial for maintaining the health and safety of your Acura RL.

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