What is the reason for the Audi maximum speed 4000rpm fault?

[LaLydia]

Audi maximum speed 4000rpm fault has the following reasons: 1. Excessive carbon deposits in the engine: This situation is mainly caused by gasoline not being fully absorbed into the engine, leading to carbon deposits. Due to incomplete combustion of the vehicle, it results in engine shaking and increased fuel consumption. 2. Throttle or fuel injector not cleaned for a long time: Spark plugs not replaced for a long time, or even intake manifold failure, or engine misfire, which will affect fuel atomization and combustion, leading to a series of problems. 3. Engine oil quality does not match the engine: For example, 0W20 is suitable for Japanese cars with smooth inner walls, 5W30 is suitable for European and American cars, and the high viscosity of 0W40 is suitable for older cars. Once the oil viscosity is too high, it will lead to increased fuel consumption, carbon deposits, and other situations.