2018 Jeep Renegade Has Rough Idle

Diagnosing Causes of Rough Idling in Your 2018 Jeep Renegade and How to Restore Smooth Performance

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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 2018 Jeep Renegade 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 2018 Jeep Renegade 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 2018 Jeep Renegade, and what diagnostic steps should be taken?

When diagnosing a rough idle in your 2018 Jeep Renegade, it's crucial to follow a structured diagnostic approach that prioritizes simpler issues before tackling more complex ones. Begin by examining the spark plugs, as worn or faulty plugs can significantly impact engine performance. If they show signs of wear or damage, replacing them is a straightforward and effective first step. Next, inspect the air filter; a dirty or clogged filter can restrict airflow to the engine, worsening idle problems. If the air filter is compromised, replacing it is an easy and cost-effective solution. Afterward, turn your attention to the fuel system, checking both the fuel filter and injectors for blockages that could disrupt fuel delivery. Cleaning or replacing these components may be necessary to ensure optimal fuel flow. Additionally, look for vacuum leaks, as these can alter the air-fuel mixture and contribute to rough idling. Inspect vacuum hoses for any cracks or disconnections. The throttle body is another critical area to check; a buildup of dirt can impede its function, so a thorough cleaning might resolve idle issues. Finally, consider the engine sensors, as faulty sensors can mislead the engine management system. Running a diagnostic scan can help identify any sensor-related problems that need addressing. By systematically following these steps, you can effectively identify and resolve the underlying causes of a rough idle in your Jeep Renegade.

What are the common causes of a rough idle in a 2018 Jeep Renegade?

When dealing with a rough idle in your 2018 Jeep Renegade, it's essential to understand the common problems that could be at play. One frequent culprit is a dirty or clogged air filter, which can significantly restrict airflow to the engine, leading to performance issues. Additionally, faulty spark plugs are another common cause; if they are worn or malfunctioning, they can result in engine misfires that manifest as a rough idle. Another area to inspect is the vacuum system, as any leaks can disrupt the delicate air-fuel mixture necessary for smooth engine operation. Fuel system issues, such as a clogged fuel filter or malfunctioning fuel injectors, can also contribute to rough idling by affecting the engine's fuel delivery. Lastly, a faulty oxygen sensor can throw off the air-fuel ratio, further complicating the idle quality. By addressing these potential issues through regular maintenance and timely repairs, you can help ensure your Jeep Renegade runs smoothly and efficiently.

How urgent is it to address the rough idle in my 2018 Jeep Renegade?

Addressing a rough idle in your 2018 Jeep Renegade is crucial for maintaining the vehicle's performance and longevity. Ignoring this symptom can lead to a cascade of problems, including decreased fuel efficiency and engine misfires, which not only affect your driving experience but can also result in costly repairs down the line. A rough idle often indicates underlying issues such as faulty spark plugs, vacuum leaks, or fuel system malfunctions that can worsen over time if left unattended. By prioritizing timely repairs, you not only safeguard your engine from potential damage but also enhance your vehicle's overall efficiency. Therefore, it is essential to take immediate action to diagnose and resolve the rough idle, ensuring your Jeep remains reliable and safe on the road.

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