2011 INFINITI FX35 Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2011 INFINITI FX35 and Solutions for a Smoother Ride

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Reviewed by

Andrew Hajjar

Written by RepairPal Car Genius

Updated January 14, 2025

21% chance it's the

Spark Plugs

15% chance it's the

Ignition Coil

64% chance it's

Something else

The most common reasons a 2011 INFINITI FX35 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.

What are the best INFINITI repair shops?

RepairPal Certified shops can diagnose and repair your 2011 INFINITI FX35 engine and performance issues. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.

How much does it cost to fix a 2011 INFINITI FX35 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:

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.
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.
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.
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 steps to diagnose a rough idle in a 2011 INFINITI FX35?

To effectively diagnose a rough idle in a 2011 INFINITI FX35, it's essential to adopt a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by using an OBD-II scanner to check for any fault codes, as these can quickly point you to specific issues within the engine. Next, inspect the spark plugs for wear or fouling, since faulty plugs can lead to misfires that contribute to an unstable idle. Following this, examine the ignition system components, including coils and wires, to ensure they are functioning correctly. A clean air intake system is crucial, so check the air filter and intake for any blockages that could hinder performance. Additionally, inspect the fuel system, focusing on injectors and filters, to rule out fuel delivery problems. Don’t forget to check for vacuum leaks by examining hoses, as these can significantly affect engine performance. Testing the mass airflow sensor is also vital, as a malfunction here can disrupt the air-fuel mixture. Finally, inspect the throttle body for any carbon buildup that could impede airflow. By following this structured diagnostic approach, you can identify and address the root causes of a rough idle, ultimately enhancing your vehicle's performance.

What are the common causes of a rough idle in a 2011 INFINITI FX35?

When dealing with a rough idle in a 2011 INFINITI FX35, it's essential to consider several common problems that could be at play. 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 performance issues. Additionally, inspect the spark plugs, as worn or faulty plugs can cause misfiring, which directly contributes to a rough idle. Another critical component to examine is the vacuum system for any leaks, as these can disrupt the air-fuel mixture necessary for smooth engine operation. Fuel system issues, such as a clogged fuel filter or a malfunctioning fuel pump, can also impact engine performance and should not be overlooked. Furthermore, the mass airflow sensor plays a vital role in regulating the air-fuel mixture, and if it malfunctions, it can lead to rough idling. Lastly, the idle air control valve is crucial for maintaining the engine's idle speed; if it is dirty or faulty, it can cause significant fluctuations in idle quality. By addressing these common issues through regular maintenance and timely repairs, you can effectively resolve the rough idle problem in your INFINITI FX35.

How urgent is it to address the rough idle in a 2011 INFINITI FX35?

Addressing a rough idle in your 2011 INFINITI FX35 is not just a matter of comfort; it is crucial for the overall health of your vehicle. A rough idle can signal various underlying problems, such as dirty fuel injectors or a malfunctioning oxygen sensor, which, if ignored, may escalate into more severe issues. Neglecting these symptoms can lead to decreased fuel efficiency and engine misfires, ultimately resulting in costly repairs. Moreover, a rough idle can indicate that your engine is not operating optimally, which could compromise your vehicle's performance and safety. Regular maintenance and prompt diagnosis of such issues are essential to prevent further damage and ensure the longevity of your vehicle. Therefore, it is imperative to address a rough idle as soon as it is noticed to avoid potential complications and maintain the reliability of your INFINITI FX35.

Related 2011 INFINITI FX35 Problems

Read about related problems experienced by other INFINITI FX35 drivers like you.

Erratic or High Idle After Cleaning Throttle Body

The throttle body for the Infiniti FX35 is known for carbon buildup, and requires regular, light cleaning to maintain peak performance. After cleaning the throttle body, many owners notice a very high idle, erratic (bouncing) idle, and unpredictable power surging. The cause is normal ECU adaptation: When the throttle body builds up carbon, the rate of airflow is slightly decreased. The vehicles computer reads this decrease in air volume, and adjusts the throttle body settings to maintain the proper engine idle speed. When the carbon is cleaned out, the ECU now registers too much air, and cannot adjust back to the original settings. While it is trying to change settings, the idle will bounce from low to high, and the car will surge forward at times. It has been recommended to simply wipe inside the throttle body every 12,000 miles, and never to touch the flap inside. Also, the cleaning procedure may be best left to a qualified technician. The solution can be as simple as disconnecting the battery for at least an hour, having the dealer reset the computer, or, in extreme cases, replace the throttle bodies.

6 model years affected

Avg Mileage: 1200,000

11 others reported problem

1 comment

Jaguar XKR rough idling issue with trouble codes indicating random multiple misfire in one bank

Some Jaguar XKR owners report experiencing rough idling issues accompanied by trouble codes indicating random multiple misfires, such as P0300, P0302, and P0304, which are linked to specific cylinders like cylinder 2 and cylinder 4. These owners often identify potential causes including vacuum leaks, spark plug problems, or ignition coil failures. Additionally, some report symptoms of fuel starvation, prompting checks of fuel pressures for accurate diagnosis. Issues with the supercharger bypass valve have also been noted as a contributing factor to rough idling. Furthermore, maintaining the correct air-to-fuel ratio is crucial, as any discrepancies can exacerbate misfires and idling issues. To resolve these problems, owners may need to reset fault codes, check fuel pressure, inspect the supercharger bypass valve, and ensure optimal air-to-fuel ratios.

1 model year affected

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