What causes the Passat to shake when driving between 100 and 120 km/h?

[EmmaLynn]

Passat shaking between 100 and 120 km/h can be attributed to the following reasons: 1. Severe engine carbon deposits: The most common cause of car shaking is excessive dirt on the throttle body or carbon buildup in the fuel injectors. When there is too much carbon inside the engine, the gasoline sprayed by the cold-start injector is largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts. This makes starting difficult, and after ignition, the gasoline adsorbed on the carbon deposits is sucked into the combustion chamber by the engine's vacuum, making the mixture too rich. The fluctuating air-fuel mixture causes idle shaking after a cold start. 2. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak sparking from the spark plugs can also lead to such symptoms. 3. Aging engine components: Car shaking can also be related to worn engine mounts. Engine mounts are responsible for absorbing minor vibrations during engine operation. If the mounts are faulty, these vibrations can transfer to the steering wheel and cabin, causing shaking at idle.