2011 BMW 128i Has Rough Idle

Troubleshooting Causes of Rough Idle in Your 2011 BMW 128i and How to Restore Smooth Performance

Find Repair Location
Reviewed by
Aisha
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 2011 BMW 128i has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
  • Spark Plugs: A worn or fouled spark plug can cause misfires, rough idling, and decreased fuel efficiency due to incomplete combustion.
  • 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 2011 BMW 128i 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 common causes of a rough idle in a 2011 BMW 128i?

When diagnosing a rough idle in your 2011 BMW 128i, it's essential to consider several common problems that could be affecting your vehicle's performance. One of the primary culprits is faulty spark plugs, which can lead to misfires and an unstable idle. If your spark plugs are worn or damaged, replacing them can often resolve the issue. Additionally, dirty or malfunctioning components such as the Idle Control Valve (ICV) or clogged fuel injectors can disrupt the engine's air-fuel mixture, contributing to rough idling. Another frequent cause is vacuum leaks, which are particularly prevalent in BMWs; these leaks often occur in the intake boot or the piping that connects the air filter to the throttle body. If you notice rough idling during cold starts, it may indicate problems with ignition coils, even if the spark plugs have been recently changed. Lastly, temperature sensitivity can play a role, as some drivers experience fluctuating idle RPMs during the first start of the day when temperatures are lower. By addressing these issues promptly, you can enhance your vehicle's performance and ensure a smoother driving experience.

How urgent is it to address the rough idle in my 2011 BMW 128i?

Addressing the rough idle in your 2011 BMW 128i is crucial for maintaining the vehicle's overall performance and longevity. Ignoring this symptom can lead to serious engine health issues, such as misfiring cylinders or fuel system malfunctions, which may escalate into costly repairs if left unchecked. Additionally, a rough idle can significantly affect your fuel efficiency, causing your car to consume more gas than necessary, ultimately impacting your wallet. Beyond mechanical concerns, a rough idle can also detract from your driving experience, introducing uncomfortable vibrations that can make your time on the road less enjoyable. Therefore, while it may not seem like an immediate emergency, it is wise to prioritize a diagnostic check with a professional mechanic. This proactive approach not only helps identify the root cause of the rough idle but also prevents further complications that could arise from neglecting the issue. Taking timely action ensures your BMW remains in optimal condition, enhancing both its performance and your driving comfort.

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.