What Causes Slight Shaking When Starting a Small Car?

[ORowan]

Small car starting with slight shaking may be caused by the following reasons: 1. Tire balance issues leading to vehicle deviation: There are several situations of tire imbalance, one is caused by prolonged use leading to steel rim deformation, another is due to drive shaft deformation. 2. Severe engine carbon buildup: When there is excessive carbon buildup inside the engine, it can cause idle shaking after cold start. This happens because when carbon deposits are excessive, a large amount of sprayed fuel gets absorbed by the carbon deposits, making the air-fuel mixture too lean and causing difficulty in starting. The vehicle can only start when the mixture reaches a certain level, but then due to excessive carbon deposits, the mixture in the cylinders becomes too rich, resulting in shaking when starting the car.