What to Do if Volkswagen Passat Idles Roughly?
2 Answers
Volkswagen Passat rough idling reasons are as follows: 1. Unstable oil pressure. If you have already cleaned the engine carbon deposits, washed the throttle, replaced the oil pad and spark plugs, etc., and still find the car body shaking during idling, it is recommended to go to a 4S shop to check the fuel supply pressure and the intake pressure sensor. If the fuel pump supply pressure is abnormal, or the intake pressure sensor value is incorrect and not working well, it will cause the car body to shake. The best solution is to check the oil pressure and replace parts if necessary. 2. Engine parts may be aging, such as engine mounts aging may cause the car body to shake. Engine mounts are the shock absorption system of the engine, responsible for absorbing the slight vibrations of the engine during operation. If there is a problem with the engine mounts, these vibrations will be transmitted to the steering wheel and the driving compartment. 3. The engine throttle is too dirty, or the injector has too much carbon deposit causing shaking. When there is too much carbon deposit, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in too lean a mixture for cold start, making it difficult to start. The gasoline adsorbed on the car's carbon deposits will be sucked into the cylinder by the engine's vacuum suction for combustion, making the mixture too rich. The engine's combustible mixture will be sometimes lean and sometimes rich, causing rough idling. The solution is to clean the fuel system and check whether the idle speed motor has carbon deposits that should be cleaned.
I've been driving a Volkswagen Passat for many years and have encountered the issue of idle vibration before. It felt like the engine was dancing, completely unstable. This problem is often caused by aging spark plugs, excessive carbon buildup, or issues with the ignition coil. For example, dirty spark plugs can fail to ignite properly, leading to engine imbalance; carbon deposits on the throttle body can also affect air intake. I usually start by checking the simpler components: using a wrench to see if the spark plugs are blackened, and if I have the tools, I remove them for cleaning or replacement—a new pair only costs a few dozen yuan. If there's no improvement, it might be due to clogged fuel injectors or a dirty air filter, which need timely cleaning. Don’t forget to check if the engine mount rubber pads are loose, as this is also a common cause. Engine vibration not only affects driving comfort but also increases fuel consumption and can damage the engine over time. So, I recommend trying basic maintenance yourself first. If the problem persists, take it to a repair shop to check the fault codes—never ignore small issues.
