Why Your Mercedes is Rough Idling


Mercedes Benz is a highly-reputable, German-engineered vehicle. That’s why it can be so concerning when the normally smooth idling starts feeling rough. It can cause you worry about what’s wrong and how you’re going to get it fixed.

If you have questions, we are here to help. Foreign Affairs Auto is the best-rated and most experienced shop for your Mercedes.  We want to walk you through our inspection results, advise you of your options, and help create a plan for any necessary repairs. If you notice any cause for concern in your Benz, then Foreign Affair Auto is for you.

Rough Idling in Your Mercedes

To know what rough idling means, we first need to define idling. Idling is the term for what the engine does when your car is on but you’re not in motion. Usually, the engine should run smooth and steady. When it’s running as designed, the air-to-fuel ratio, the fuel, the ignition, and the emission are all running properly.

Rough idling is when there are shaking sensations and excessive vibrations when your car is not in motion. Sometimes it can be very intense. This can be felt, for example, while sitting at a red light.

Common Causes of Rough Idling

There are many reasons a vehicle could be idling roughly. Below are some of the most common causes:

  • Ignition System: Many things can go wrong with the ignition system. It could be a worn out spark plug, defective ignition coils, or a cracked distributor cap. These, in addition to damaged ignition wires, are some reasons for engine misfiring. When a misfiring engine is unable to burn the fuel in the combustion chamber, you may experience rough idling.
  • Mass AirFlow (MAF) sensor: This unit has the job of measuring the flow of air in fuel-injected engines. If it is faulty or even dirty, it can cause rough idling and stalled engines while idling.
  • Oxygen Sensor: A faulty or malfunctioning oxygen sensor will fail to monitor and analyze the oxygen amount in your car’s exhaust system. This can lead to unnatural air/fuel mixtures that can cause rough idling.
  • Air Filter: If the air-to-fuel ratio isn’t right, it can cause the engine to lack enough air. A clogged air filter should be one of the first things to check if you experience rough idling in your Mercedes.
  • PCV Valve: A dirty PCV valve means too much air will be in the engine. This will also cause idling roughly.
  • Vacuum Leaks: Another possible reason behind idling roughly are leaks from vacuum hoses that are damaged or cracked or loose. This will also affect the air-to-fuel ratio in the engine. A larger leak may even result in engine stalling when idling. While the car is driving, you might hear a sucking or hissing noise that may indicate a leak.
  • Idle Air Control (IAC): This component of your vehicle regulates how much air enters the engine and controls the idle speed. IAC valves can accumulate carbon over time and that can limit how much air enters the engine. Similar to vacuum leaks, in worst-case scenarios, a dirty IAC can cause stalling engines.

Are you sick of high maintenance cost at the dealership to maintain the car you love? Find yourself searching Google for Mercedes service near me, Mercedes repair me or Mercedes Services West Palm Beach? Do yourself a favor and click on Foreign Affairs! We have been dedicated to servicing Mercedes and our customers in West Palm Beach FL for decades, Schedule an appointment for service. You can find us located at 1681 N Military Trail, West Palm Beach, FL 33409.