2021 Ford Mustang Mach-E Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2021 Ford Mustang Mach-E 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 Mustang Mach-E 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 Mustang Mach-E 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 potential causes of a rough idle in a 2021 Ford Mustang Mach-E, and what diagnostic steps should be taken?

When diagnosing a rough idle in a 2021 Ford Mustang Mach-E, it's crucial to take a methodical approach that prioritizes simpler issues before delving into more complex diagnostics. Begin by inspecting the spark plugs, as worn or damaged plugs can significantly impact engine performance and lead to an unstable idle. Next, check the air filter; a clogged or dirty filter can disrupt the air-fuel mixture, exacerbating idle problems. Following this, examine the fuel system for any blockages, particularly in the fuel filter or injectors, as these can also contribute to rough idling. Utilizing a diagnostic scanner to check for error codes can reveal underlying issues that may not be immediately apparent. Additionally, assess the throttle body for cleanliness and proper function, since a dirty throttle body can hinder idle quality. Finally, ensure the Positive Crankcase Ventilation (PCV) valve is in good condition, as a faulty valve can lead to erratic idling. By systematically addressing these components, you can effectively identify and resolve the causes of a rough idle in your Mustang Mach-E, ensuring a smoother driving experience.

What are the common problems that could cause a rough idle in a 2021 Ford Mustang Mach-E?

When dealing with a rough idle in your 2021 Ford Mustang Mach-E, 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, inspect the spark plugs, as worn or faulty plugs can lead to misfires, which are a frequent cause of rough idling. Another critical component to examine is the vacuum system; any leaks can disrupt the air-fuel mixture, further exacerbating idle issues. Fuel system problems, such as a clogged fuel filter or a malfunctioning fuel pump, can also impact engine performance and contribute to a rough idle. Don't overlook the oxygen sensor, as a malfunction here can alter the air-fuel ratio, leading to performance issues. Lastly, consider the throttle body; carbon buildup or sensor faults can cause irregular idling. By addressing these common issues through regular maintenance and timely repairs, you can effectively resolve rough idle problems and enhance the performance of your Mustang Mach-E.

How urgent is it to address the rough idle in my 2021 Ford Mustang Mach-E?

Addressing a rough idle in your 2021 Ford Mustang Mach-E is crucial for maintaining the vehicle's performance and longevity. A rough idle can be a symptom of various underlying issues, such as faulty spark plugs, fuel system malfunctions, or air intake problems. Ignoring these symptoms can lead to more severe consequences, including decreased fuel efficiency, engine misfires, and even significant damage to engine components over time. The urgency of resolving a rough idle cannot be overstated, as neglecting it may result in costly repairs and diminished vehicle safety. For those inclined to tackle this issue themselves, it is essential to conduct a thorough inspection and consider seeking professional assistance if the problem persists. Timely intervention not only enhances your driving experience but also safeguards your investment in the Mach-E, ensuring it remains in optimal condition for years to come.

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