2021 Ford Explorer Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2021 Ford Explorer and How to Resolve Them

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Reviewed by
Devin Cabugcal
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 Ford Explorer 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 Ford Explorer 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 and fix a rough idle in a 2021 Ford Explorer?

To effectively diagnose and fix a rough idle in your 2021 Ford Explorer, start with a systematic approach that prioritizes simpler checks before moving on to more complex diagnostics. Begin by using an OBD-II scanner to identify any error codes that could point to the underlying issue. Next, inspect the spark plugs for signs of wear, as faulty plugs can significantly impact engine performance. Following this, examine the air filter for dirt or clogs, which can restrict airflow and affect idle quality. It's also crucial to check for vacuum leaks by inspecting hoses for cracks or disconnections, as these can disrupt the air-fuel mixture. After addressing these initial checks, turn your attention to the fuel system, looking for clogged injectors or issues with the fuel pressure regulator. Cleaning the throttle body is another important step, as carbon buildup can hinder engine performance. Additionally, ensure the PCV valve is functioning correctly, as a malfunctioning valve can contribute to rough idling. Don’t overlook the engine mounts; worn or damaged mounts can lead to excessive vibrations. If all else fails, consider performing an idle relearn procedure to recalibrate the engine's idle speed. By following this structured diagnostic approach, you can effectively identify and resolve the rough idle issue in your Ford Explorer.

What are the common problems that could cause a rough idle in a 2021 Ford Explorer?

When dealing with a rough idle in your 2021 Ford Explorer, it's essential to understand the common problems that could be at play. One of the first areas to check is the air filter; a dirty or clogged filter can significantly restrict airflow to the engine, resulting in an uneven idle. Additionally, the oxygen sensor plays a crucial role in maintaining the correct air-fuel mixture, and if it's faulty, it can lead to performance issues. Another potential culprit is vacuum leaks, which can disrupt the balance of air and fuel entering the engine, further contributing to rough idling. Fuel system problems, such as a clogged fuel filter or malfunctioning fuel injectors, can also hinder engine performance. Don't overlook the condition of your spark plugs; worn or fouled plugs can impair combustion, leading to a rough idle. Lastly, inspect the throttle body for any carbon buildup or sensor issues, as these can affect airflow and exacerbate idle problems. By systematically addressing these common issues, you can effectively troubleshoot and resolve rough idle concerns in your Ford Explorer.

How urgent is it to address the rough idle in a 2021 Ford Explorer?

Addressing a rough idle in your 2021 Ford Explorer should be treated with a sense of urgency, as it can indicate underlying engine problems that may escalate if ignored. A rough idle not only affects the vehicle's performance but can also lead to decreased fuel efficiency and increased wear on engine components. Over time, these issues can result in more significant damage, leading to costly repairs that could have been avoided with timely intervention. Moreover, neglecting a rough idle can compromise your vehicle's safety, as it may affect the engine's responsiveness and overall reliability. Therefore, it is crucial to prioritize diagnosing and resolving this issue promptly, ensuring your Explorer operates smoothly and efficiently while safeguarding your investment in the vehicle.

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