2019 BMW 740i XDrive Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2019 BMW 740i xDrive and How to Resolve Them

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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 2019 BMW 740i xDrive 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 2019 BMW 740i xDrive 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.

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 initial diagnostic steps to take for a rough idle in a 2019 BMW 740i xDrive?

When faced with a rough idle in your 2019 BMW 740i xDrive, the first step is to utilize a diagnostic scanner to check for any fault codes stored in the vehicle's computer system. These codes can offer critical insights into the underlying issues affecting engine performance. Next, inspect the air intake system for any leaks or clogs, ensuring that the air filter is clean and properly installed, as this can significantly impact engine efficiency. Following this, examine the fuel system components, including the fuel filter and injectors, to ensure that fuel delivery is optimal. Additionally, inspect the ignition system by checking the spark plugs and ignition coils for wear, as faulty components here can lead to a rough idle. It’s also important to verify the functionality of key engine sensors, such as the mass airflow and oxygen sensors, since malfunctioning sensors can disrupt engine performance. Lastly, don’t overlook the Positive Crankcase Ventilation (PCV) system; checking for clogs or leaks here can also help resolve idle issues. By systematically following these diagnostic steps, you can effectively identify and address the causes of a rough idle in your BMW, potentially saving time and repair costs.

What are the common problems that could cause a rough idle in a 2019 BMW 740i xDrive?

When diagnosing a rough idle in a 2019 BMW 740i xDrive, it's crucial to explore several common issues that may be affecting the vehicle's performance. A dirty or malfunctioning mass airflow sensor can significantly disrupt the air-fuel mixture, leading to an uneven idle. Additionally, vacuum leaks within the intake system can allow unmetered air to enter the engine, further complicating the idle situation. Worn spark plugs or faulty ignition coils are also key contributors, as they can cause misfires that manifest as a shaky idle. A clogged fuel filter may restrict fuel flow, adversely affecting engine performance at idle. Moreover, issues with the idle control valve can interfere with the engine's idle speed, while a malfunctioning throttle body can disrupt air intake, resulting in irregular idling. By identifying and addressing these common problems, DIY enthusiasts can effectively troubleshoot and resolve rough idle issues in their BMW, leading to a smoother and more enjoyable driving experience.

How urgent is it to address the rough idle in a 2019 BMW 740i xDrive?

Addressing a rough idle in your 2019 BMW 740i xDrive should be treated with a sense of urgency, as neglecting this issue can lead to more severe engine problems and costly repairs. A rough idle often indicates underlying issues such as fuel delivery problems, ignition system failures, or vacuum leaks, which can progressively worsen if not resolved. By taking the time to diagnose and fix the rough idle, you not only enhance your vehicle's performance but also improve fuel efficiency and reduce harmful emissions. Moreover, regular maintenance and prompt repairs can prevent the escalation of minor issues into major ones, ensuring the longevity of your vehicle. Therefore, while it may not seem like an immediate emergency, addressing a rough idle promptly is crucial for maintaining the overall health and safety of your BMW.

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