What Causes the Passat to Shake at Idle but Stop Shaking When Accelerating?
2 Answers
Passat shakes at idle but stops shaking when accelerating due to the following reasons: 1. Severe carbon buildup inside the engine: This often manifests as carbon deposits on the throttle body, fuel injectors, spark plugs, and pistons. When these deposits accumulate to a certain extent, they absorb combustion heat and can even cause detonation or knocking. If the fuel injectors become clogged, it can lead to poor atomization of fuel, resulting in dripping and smoke, which not only increases fuel consumption but also pollutes the environment. 2. Ignition system issues: These are usually caused by excessive carbon buildup on the spark plugs or insufficient ignition voltage, leading to misfiring. This can result in single or multiple cylinders misfiring, causing the engine to lose power and shake. Severe shaking can put the engine in a state between stalling and firing.
I used to drive a Passat, and it shook badly at idle, but became smooth when I stepped on the accelerator. This issue is quite common. It might be due to old spark plugs that haven't been replaced, causing inaccurate ignition timing and uneven combustion at idle. Alternatively, the throttle body could be clogged with carbon deposits, restricting the intake airflow and leading to unstable idle. I also considered cleaning the throttle body myself with a cleaner, but it's best to visit a professional shop to check the OBD data for fault codes. Otherwise, prolonged neglect could increase fuel consumption and put more strain on the engine. Regularly replacing spark plugs and cleaning the throttle body can prevent this. I always remind the technician to check this during every maintenance. From a safety perspective, the shaking at idle can be uncomfortable when stopped at a red light and might affect judgment. Addressing it early saves both hassle and money.
