What is the reason for gearbox jitter?

Causes of gearbox jitter: 1, too much carbon deposit: if the engine has too much carbon deposit, it will also absorb a certain amount of engine oil, which will make the mixture at the start too low. When the gasoline absorbed by carbon deposits is saturated, the engine starts to work normally. However, when the mixture is ignited, the gasoline adsorbed by carbon deposit will be sucked into the cylinder by vacuum suction, which will cause the mixture to be too rich, thus causing the engine to shake. 2. The throttle or air filter is too dirty: the air filter is too dirty, the air entering the engine cylinder is not enough, and the mixing ratio is unbalanced, resulting in insufficient engine power and jitter. If the throttle valve is too dirty and cannot be closed tightly, the mixture will be too thin at idle speed and the engine power will be insufficient. 3. Spark plug failure: If the spark plug is used for a long time, it will increase the gap of the spark plug or accumulate too much carbon at the ignition point, resulting in poor ignition of the spark plug or low ignition energy, resulting in cylinder loss, power reduction and engine jitter. 4. Aging of engine parts: The engine foot pad cannot play a buffering role due to aging.