Why does the new Audi car shake during cold start?

[Kara]

The following are the reasons why a new Audi car shakes during cold start: 1. The engine temperature is too low, and the temperature of both fuel and lubricating oil is very low. During a cold start, a richer air-fuel mixture is required, which in turn demands 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 a decrease in ignition energy, causing the car to shake. 2. Uneven operation among cylinders causes engine shaking. In multi-cylinder engines, significant differences in ignition energy between cylinders, as well as varying degrees of wear in pistons and piston rings, can result in inconsistent compression ratios. This leads to uneven power output from the engine, causing shaking. 3. Incorrect air-fuel mixture ratio leads to shaking. During a cold start, if certain engine sensors or some sensor signals have large errors, the ECU may make incorrect judgments. This can result in errors in fuel injection timing and ignition timing control, leading to engine shaking.