What Causes Rough Running in Your BMW?

What Causes Rough Running in Your BMW?

Rough running is a term used in motoring to describe the noticeable shuddering, sounds, and slow acceleration of an idling vehicle. For many drivers experiencing rough running can completely defeat the purpose of owning a luxury vehicle such as a BMW, which should make driving feel as smooth and as comfortable as possible. Some drivers even think it is simply a part of a vehicle's aging process and is an unavoidable annoying. This simply isn’t true.

Rough running is actually completely preventable and can be remedied by a professional mechanic. In this article, we’ll be exploring just what those factors are and why they can make your BMW run rough.

Symptoms of Rough Running

First, let's take a closer look at some of the symptoms of rough running. You may not experience all of these or may only notice them, so it’s good to be well informed.

Acceleration is a Struggle

Luxury vehicles such as BMW should practically glide as they accelerate, with a soft purr being the only sign of any exertion from the engine. However, in a vehicle that is running rough, a loss of power when accelerating is keenly felt, as are strained engine sounds.

Low Fuel Economy

Poor mileage or poor fuel economy is caused by rough running because, for whatever reason, the engine isn’t performing at optimum levels, meaning that more fuel is being used than normal.


Rough running can cause misfires as the engine system is under strain. These misfires can be caused by mechanical failures, ignition failures, or fuel problems.

Illumination of the Check Engine Light

As rough running is typically a signifier of engine issues, if the problem becomes more severe or persistent, your BMW’s onboard computer may assume an engine problem and will illuminate the check engine light.

What causes rough running?

There are a variety of different causes of rough running, but overall, rough running signals that something is causing your engine to not run as designed. Any problem like this should always be investigated by a professional. Some of the common culprits include:

The Spark Plugs

The spark plugs are incharge of ignition the mixture of air and fuel in your engine. These parts work hard and can become worn out if not maintained, resulting in misfires and rough running due to poor ignition.

The Fuel Injectors

Responsible for adding the fuel into the engine, fuel injectors can cause rough running if they develop a fault such as clogging, which affect the rate of fuel flow into the engine.

The Mass Airflow Sensor

The MAF sensor monitors the amount of air entering the engine and relays this information to the onboard computer so it can provide the correct amount of fuel in response. Therefore, if this part fails, the computer is left guessing, which can lead to an imbalance of fuel and air, thus causing rough running.

The Tires

The only cause of rough running not found under the good is the tires. The tires can cause rough running through their contact with the ground. If they are poorly maintained, such as bald or with uneven wear, your ride will become more rough with more road bumps felt in the cabin. Your BMW may also struggle to accelerate due to the lack of grip on the road, resulting in an overall rough running.

Rough Running Can be Avoided

It’s important to remember that rough running is completely avoidable, so you shouldn’t settle for anything other than smooth driving, particularly from a luxury vehicle such as a BMW. Rough running won’t go away on its own, as it is a sign of part failure somewhere within your vehicle. Therefore, should you notice your BMW start to run rough, you should respond quickly and take your car in for servicing.

We are on hand to help at Import Motorworx. Drivers of Lawndale, Culver City, West Los Angeles, and South Bay, CA can stop in or call for a consultation. We are experts in European cars, such as BMW. Our repairs and servicing are comprehensive, and when it comes to motoring problems, our technicians leave no stone unturned. In fact, we are so sure you’ll drive away happy that we offer a 2-year/24,000 mile warranty as our guarantee.

Written by Import MotorWorx