Your Volkswagen is a well-designed machine that usually provides a smooth and quiet driving experience, but sometimes you may observe your engine shaking or chugging while it runs. It may vibrate more than usual and the drive can feel rough. You might even feel these vibrations through the steering wheel, and the jump of an engine misfire.

If your Volkswagen is idling rough, it can shake your confidence that your car can be relied upon. Fortunately, you can get it taken care of and avoid the pain of much more costly repairs to your engine if you pay attention to how your car feels.

Definition of Idling

Idling is what happens when you start your car’s engine and allow it to run without touching the accelerator or otherwise putting the car into gear. A healthy engine will idle at around 1,000 RPM, and the needle on your tachometer should be mostly stationary at a single RPM and not moving wildly between a sizable range.

Your car’s accessories, such as the stereo system, clock, lights, and blowers, should be able to operate continuously and not be interrupted. This is because the idling engine is producing enough power for these systems.

Rough Idling

Rough idling looks like the opposite of what we described above. Your tachometer jumps around like it’s a ping pong ball, and the power to the accessories fluctuates noticeably. You will feel vibrations that shake the car emanating from the engine.

Several things can cause rough idling. To start with, you should try to observe under what conditions the rough idling occurs. For example, does it happen when the engine has been warmed up, or only on a cold start? Pay attention to whether it’s rough all the time, and whether there are other signs, such as smoke coming from the engine or noises like banging or knocking. If you can share any of this information with your mechanic, it will speed up their ability to diagnose the problem by helping them zoom in on it more quickly.

Your Volkswagen will have a computerized engine that will collect data about the engine’s performance and trigger a problem code when it reads that things aren’t working right. This causes the check-engine indicator to light up on your dashboard. When this happens, your mechanic can attach a device that will reveal the problem code and might identify where the problem is coming from. This may not work, but it is often the first step.

Causes of Rough Idling

The below causes are by no means the only possible reasons of rough idling, but they are among the most common. Whenever you observe your engine is idling rough, you will want to bring it in to be serviced as soon as you can to avoid costly repairs down the road.

• The Fuel Injector is Clogged or Dirty: The fuel injector is designed to pass fuel into the engine with precision in terms of the angle and amount to create the best performance from the engine. If your fuel injectors have gotten clogged with soot or dirt, they cannot do their job effectively, causing an improper mix of fuel and air in the engine. They may need to be cleaned to fix the problem.
• A Vacuum Leak: The network of hoses delivering fuel and air to the engine of your Volkswagen is a closed system that is driven by a vacuum created by the intake manifold. As these hoses wear out, they can leak, causing this vacuum to be compromised. If too much air enters the engine, it will lower the ratio of air to fuel in the engine, causing misfires, which lead to rough idling.
• Damaged or Dirty Spark Plugs: Spark plugs are the components that trigger the ignition of the air and fuel mixture in the combustion chamber of the engine, so if they get damaged or dirty, they won’t ignite at the right time. This will throw off the timing of your engine or cause misfires, and lead to the engine running roughly.

Masters European & Japanese Auto Repair

We have service locations in Corte Madera, Larkspur, Sausalito, Tiburon, Mill Valley, CA where our ASE-certified technicians are waiting to service your Volkswagen and get you back on the road with confidence in the reliability of your car.

We specialize in European and Japanese imports, just like your Volkswagen, and have satisfied customers throughout the Mill Valley region. Call us to set up your appointment today and allow us to earn your patronage.

* Volkswagen Car image credit goes to: nrqemi.