2004 Acura RSX Has Rough Idle

Common Causes of Rough Idling in Your 2004 Acura RSX 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 2004 Acura RSX 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 2004 Acura RSX 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 a rough idle in a 2004 Acura RSX?

To effectively diagnose a rough idle in your 2004 Acura RSX, start with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Begin by inspecting for vacuum leaks, as even minor cracks in the vacuum hoses can significantly impact engine performance. Next, examine the air filter; a clogged filter can disrupt the air-fuel mixture, leading to an unstable idle. Following this, check the spark plugs for wear or fouling, as these can cause misfires that contribute to rough idling. It’s also essential to test the ignition system, including coils and wires, to ensure they are functioning properly. Utilizing an OBD-II scanner can help identify any error codes that may indicate specific issues. Don’t overlook the fuel system; inspect the fuel injectors and filter for blockages or malfunctions. Additionally, a thorough examination of the throttle body is crucial, as dirt or malfunction can hinder air intake. Finally, verify the operation of the idle air control valve to ensure it maintains the correct idle speed. By following this structured diagnostic approach, you can effectively identify and resolve the underlying causes of a rough idle in your vehicle.

What are the common causes of a rough idle in a 2004 Acura RSX?

When diagnosing a rough idle in a 2004 Acura RSX, it's essential to consider several common problems that could be affecting engine performance. One of the primary culprits is a vacuum leak or a malfunctioning Positive Crankcase Ventilation (PCV) valve, which can disrupt the air-fuel mixture necessary for smooth engine operation. Additionally, issues related to the air-fuel mixture itself, such as faulty fuel injectors, a malfunctioning Exhaust Gas Recirculation (EGR) valve, or low engine compression, can lead to an unstable idle. A clogged fuel filter may also restrict fuel flow, contributing to rough idling. Furthermore, problems within the ignition system, including worn spark plugs or ignition coils, can cause misfires that manifest as a rough idle. It's also worth checking the Idle Air Control Valve (IACV), as it plays a crucial role in regulating engine idle speed; cleaning or replacing this component can often resolve idle issues. Regular maintenance, such as ensuring proper coolant circulation and cleaning the IACV, can help prevent these problems and keep your RSX running smoothly.

How urgent is it to address the rough idle in a 2004 Acura RSX to prevent potential engine damage or safety risks?

Addressing a rough idle in your 2004 Acura RSX is not just a matter of comfort; it is crucial for the safety and longevity of your vehicle. A rough idle can signal serious underlying problems such as engine misfires, clogged fuel injectors, or ignition system failures. Ignoring these symptoms can lead to decreased fuel efficiency, increased emissions, and potentially severe engine damage over time. Moreover, a rough idle can compromise your vehicle's overall performance, making it less reliable and safe to drive. Therefore, it is essential to take immediate action when you notice this issue. Regular maintenance and prompt attention to rough idling can prevent further complications, ensuring that your Acura RSX remains in optimal condition and safe on the road. Don't wait for the problem to escalate; addressing it early can save you time, money, and ensure your vehicle's reliability.

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