Why does the Audi A6 shake when just started?

[DelEmmett]

Audi A6 shaking when just started may be caused by the following specific reasons: Poor tire balance condition: The first possible reason is poor tire balance condition. The owner needs to perform a four-wheel alignment and dynamic balance as soon as possible. If the vehicle does not deviate, just performing tire dynamic balance is sufficient. Ignition system problems: During cold starts, the engine requires a richer air-fuel mixture, which needs higher ignition energy. If the spark plug gap is too large, or if the ignition coil and high-voltage coil are aged, it can lead to decreased ignition energy, causing the car body to shake. The spark plugs and distributor wires should be checked, and adjustments or replacements should be made if necessary. Fuel system problems: Fuel system issues are generally caused by fuel line blockages, leading to poor fuel supply, manifested as engine shaking, unstable idle speed, and stalling while driving. Additionally, fuel pump failure can also cause engine shaking. To determine fuel pump issues, disconnect the fuel line and check the flow rate and volume of the fuel.