2016 Ford Focus Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2016 Ford Focus and How to Resolve Them

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 2016 Ford Focus 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 2016 Ford Focus 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.

Customers with drum brake systems often specify they have lost braking power, or that the vehicle's brakes are making noise. This is because brake drums do not dissipate heat very well, so the heat from hard braking will cause stress fractures. These fractures make can make noise on the brake shoes as the drum revolves around the shoes. Lastly, the brake shoes may not be problematic, but may cause a grinding noise while stopping. This would indicate the shoes have no braking material left, and the brake shoes must be changed before the vehicle can be safely driven.

Learn more about brake shoe symptoms

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 2016 Ford Focus?

When diagnosing a rough idle in a 2016 Ford Focus, it's crucial to follow a structured diagnostic approach that begins with the simplest checks and progresses to more complex issues. Start by utilizing an OBD-II scanner to retrieve any fault codes from the vehicle's computer, as these codes can provide immediate insights into potential problems. Next, inspect the air filter; a clogged filter can severely limit airflow, impacting engine performance. After that, examine the spark plugs for signs of wear or fouling, as they are vital for proper combustion. It's also essential to evaluate the fuel system components, including the fuel filter and injectors, to ensure they are functioning correctly and delivering fuel efficiently. Pay attention to the vacuum hoses as well, since any leaks can disrupt the air-fuel mixture, leading to a rough idle. Additionally, check the Positive Crankcase Ventilation (PCV) valve, as a malfunctioning valve can negatively affect engine performance. Finally, clean the throttle body to remove any dirt buildup that could impair its operation. By systematically addressing these areas, you can effectively diagnose and resolve the issues causing a rough idle in your Ford Focus.

What are the common causes of a rough idle in a 2016 Ford Focus?

When dealing with a rough idle in your 2016 Ford Focus, it's essential to understand the common problems that could be at play. One of the primary culprits is dirty or faulty spark plugs, which can lead to engine misfires and an uneven idle. Additionally, a clogged fuel filter may restrict fuel flow, impacting engine performance and causing instability at idle. It's also crucial to check for vacuum leaks, as these can disrupt the air-fuel mixture, further contributing to rough idling. Another potential issue is a malfunctioning mass airflow sensor, which can throw off the air-fuel ratio, leading to erratic engine behavior. Problems with the idle air control valve can also result in unstable idling, while a dirty throttle body can hinder airflow, exacerbating the rough idle condition. By addressing these common issues through regular maintenance and timely repairs, you can significantly improve your vehicle's performance and ensure a smoother driving experience.

How urgent is it to address the rough idle in a 2016 Ford Focus?

Addressing a rough idle in your 2016 Ford Focus is not just a matter of comfort; it is crucial for the vehicle's overall health and performance. Ignoring this symptom can lead to a cascade of problems, including decreased fuel efficiency and engine misfires, which can ultimately result in costly repairs. A rough idle often indicates underlying issues such as faulty spark plugs, fuel system malfunctions, or air intake problems that, if left unresolved, may escalate into more serious engine damage. Moreover, a rough idle can compromise your vehicle's safety, as it may affect acceleration and handling. Therefore, it is essential to prioritize this issue and seek to diagnose and resolve it promptly, ensuring your Ford Focus runs smoothly and efficiently while prolonging its lifespan.

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.

Fixing Rough Idle Issues in Your 2016 Ford Focus | RepairPal