2020 Toyota Avalon Has Rough Idle

Resolve Rough Idle in Your 2020 Toyota Avalon for Smooth Performance

Find Repair Location
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 2020 Toyota Avalon 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 2020 Toyota Avalon 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 2020 Toyota Avalon?

When faced with a rough idle in your 2020 Toyota Avalon, it's essential to adopt a systematic diagnostic approach to identify the root cause. Start by checking the spark plugs, as worn or faulty plugs can significantly impact engine performance and lead to rough idling. Next, inspect the air filter; a clogged filter can disrupt the air-fuel mixture, exacerbating idle issues. Following this, examine the fuel system components, including the fuel injectors and fuel filter, to ensure proper fuel delivery to the engine. Utilizing an OBD-II scanner to check for error codes can provide insights into any underlying problems that may not be immediately visible. Additionally, inspect the vacuum hoses for any leaks or damage, as these can also contribute to rough idling. Finally, don’t overlook the throttle body; cleaning it of any carbon buildup can enhance airflow and improve idle quality. By methodically addressing these areas, you can effectively diagnose and potentially resolve the rough idle issue in your Avalon.

What are the common problems that could cause a rough idle in a 2020 Toyota Avalon?

When dealing with a rough idle in your 2020 Toyota Avalon, it's essential to consider several common problems that could be affecting your vehicle's performance. One of the first areas to check is the air filter; a dirty or clogged air filter can significantly restrict airflow to the engine, leading to an uneven idle. Additionally, inspect the spark plugs, as worn or faulty plugs can cause misfiring, which directly impacts engine smoothness. Another critical component to examine is the vacuum system for any leaks, as these can disrupt the air-fuel mixture and result in a rough idle. Fuel system issues, such as a clogged fuel filter or a malfunctioning fuel pump, can also contribute to poor engine performance. Furthermore, the Mass Airflow Sensor (MAF) plays a vital role in regulating the air-fuel mixture, and a malfunction here can lead to idling problems. Lastly, the Idle Air Control Valve (IACV) is responsible for maintaining the engine's idle speed; if it's faulty, it can cause significant fluctuations in idle quality. By systematically checking these components, you can identify and address the underlying issues causing a rough idle, ensuring your Avalon runs smoothly.

How urgent is it to address the rough idle in my 2020 Toyota Avalon?

Addressing a rough idle in your 2020 Toyota Avalon is critical for maintaining both the performance and safety of your vehicle. A rough idle can be a warning sign of underlying issues, such as problems with the fuel system, ignition components, or engine mechanics. If left unaddressed, these issues can escalate, leading to more severe engine damage and costly repairs. Additionally, a rough idle can negatively impact fuel efficiency, resulting in higher operating costs over time. By prioritizing the investigation and resolution of a rough idle, you not only enhance your vehicle's longevity but also ensure a safer driving experience. Taking prompt action is essential to prevent further complications and to keep your Avalon running at its best.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.