What are the reasons for an Audi A6 shaking?

[AustinFitz]

Audi A6 engine shaking can be attributed to three main reasons, as introduced below: 1. Severe carbon buildup inside the engine. When there is excessive carbon buildup inside the engine, the gasoline sprayed by the cold start injector can be largely absorbed by the carbon deposits, resulting in an overly lean mixture during cold starts and making it difficult to start. 2. Issues with the ignition system. Poor performance of the ignition system or suboptimal spark plug firing can also lead to such fault symptoms. Solution: Check if the spark plugs have excessive carbon buildup and replace them if necessary. 3. Clogged fuel injectors, which cause severe carbon buildup inside the engine, leading to inconsistent operation of each cylinder and resulting in engine shaking.