2016 BMW 740i Has Rough Idle

Diagnosing the Causes of Rough Idle in Your 2016 BMW 740i and Solutions for a Smoother Ride

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Reviewed by
Andrew Hajjar
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 BMW 740i 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 BMW 740i 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 2016 BMW 740i?

When addressing a rough idle in your 2016 BMW 740i, it's essential to adopt a methodical diagnostic approach. Begin by checking for fault codes using a diagnostic scanner, as these codes can reveal specific issues affecting engine performance. Next, inspect the air intake system for any leaks or blockages, ensuring that the air filter is clean and properly seated, as restricted airflow can significantly impact engine idle quality. Following this, evaluate the fuel system by examining components like the fuel filter and injectors to confirm that fuel delivery is consistent and unobstructed. The ignition system also warrants attention; inspect spark plugs and ignition coils for signs of wear, as faulty components can lead to misfires that contribute to a rough idle. Additionally, check the EGR valve to ensure it is functioning correctly, as a malfunctioning valve can disrupt engine performance. Lastly, don't overlook the PCV system; a faulty PCV valve can create pressure imbalances that affect idle stability. By systematically addressing these areas, you can effectively diagnose and resolve the rough idle issue in your BMW.

What are the common problems that could cause a rough idle in a 2016 BMW 740i?

When diagnosing a rough idle in a 2016 BMW 740i, it's essential to consider several common problems that could be affecting the vehicle's performance. One of the primary culprits is a dirty or faulty mass airflow sensor, which can disrupt the delicate balance of the air-fuel mixture necessary for smooth engine operation. Additionally, vacuum leaks can lead to an improper air-fuel ratio, further exacerbating idle issues. Worn-out spark plugs or faulty ignition coils are also significant factors, as they can cause engine misfires that manifest as rough idling. Another potential issue is a clogged fuel filter, which restricts fuel flow and can hinder engine performance at idle. Furthermore, problems with the idle control valve can disrupt the engine's idle speed, while a malfunctioning throttle body can negatively impact air intake, leading to similar symptoms. By addressing these common issues through regular maintenance and timely repairs, you can significantly improve the idle quality of your BMW 740i and enhance its overall performance.

How urgent is it to address the rough idle in my 2016 BMW 740i?

Addressing a rough idle in your 2016 BMW 740i is not just a matter of comfort; it is crucial for the vehicle's overall performance and safety. A rough idle can indicate serious underlying issues, such as problems with the fuel or ignition systems, which, if left unchecked, may lead to decreased fuel efficiency and even engine stalling. Ignoring these symptoms can result in significant damage to engine components, potentially leading to costly repairs down the line. Moreover, a rough idle can compromise your vehicle's reliability, making it essential to act promptly. Regular maintenance and timely repairs are key to preventing further complications and ensuring your BMW continues to perform optimally. Therefore, it is highly advisable to consult a professional mechanic at the first sign of a rough idle to safeguard your vehicle's health and longevity.

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