What is the reason for the jitter of Jetta cold car?

There are several main reasons for the start-up jitter of cold car: carbon deposition, weak ignition, low cylinder pressure, unqualified fuel and so on.

1 There is too much carbon deposit in the throttle, injector and air intake, which may be one or all of them.

When there is too much carbon deposit in the engine, the gasoline sprayed by the fuel injection head will be absorbed by the carbon deposit during cold start, which will lead to too thin mixture during cold start and make the start shake.

3 Mechanical failures such as ignition coil, spark plug and fuel injector. , resulting in cylinder missing.

4 oil pressure or cylinder pressure is low, resulting in insufficient power.

5 The fuel quality is unqualified.

6 Idle speed control valve is damaged or dirty.

7 Air leakage in the intake manifold.

8 engine arm or claw pad is damaged, etc.

9 Oil oxidation or low grade is mainly due to poor fluidity at low temperature, and engine cold start protection is not in place.

The above are the common causes of engine jitter during cold start, and some reasons need to be analyzed in detail. When the cold car starts to shake, we can consider using the method of "downshifting and stepping on the accelerator deeply" to flush the carbon deposit on the engine. If you don't change it, you need to go to the maintenance station for maintenance, and you can't solve it yourself.