In the spring of 2003, Jetta changed the throttle, injector and gasoline pump. Are they all new cars? Is there anything wrong with shifting gears or shaking?

When starting or stopping the vehicle without turning off the engine, if the vehicle body is found to shake obviously, it may mean that the vehicle has the following three situations:

1. The engine has serious carbon deposition.

The most common cause of automobile jitter is that the throttle valve is too dirty or the fuel injector has too much carbon deposit. 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 leads to the lean mixture during cold start and makes it difficult to start. In this case, only when the gasoline adsorbed by carbon deposits is saturated, it is easy to run into the car. After running into the car, the gasoline adsorbed on carbon deposits will be sucked into the cylinder by the vacuum suction of the engine for combustion, which will thicken the mixture and dilute the combustible mixture of the engine, resulting in idling jitter after cold start. The lower the temperature, the more oil is needed for cold start, and the existence of carbon deposit will affect the smooth start.

Solution: clean the oil circuit, check whether there is carbon deposit in the idle motor, and clean it.

2. Ignition system problem

Check the working conditions of spark plugs, high-voltage lines and ignition coils. The ignition system is not easy to use, and the spark plug is not in good condition, which will also lead to this failure.

Solution: Check whether there is too much carbon deposit in the spark plug and replace the spark plug.

3. The oil pressure is unstable

If you clean up the engine carbon deposit, clean the throttle, change the oil pad and spark plug, etc. You still find the car body shaking at idle speed. I suggest you go to the 4S shop to check whether the oil supply pressure and intake pressure sensors are normal. If the oil supply pressure of the oil pump is abnormal, or the intake pressure sensor has an incorrect value or works poorly, it will cause the body to shake.

Solution: Check the oil pressure and replace parts if necessary.

4, engine parts aging

Car jitter is also related to the aging of engine feet (also known as claw pads). The engine foot is actually the damping system of the engine. The engine foot is responsible for absorbing slight vibration when the engine is running. If there is something wrong with the engine foot, these vibrations will be transmitted to the steering wheel and cab, causing idling jitter.

Solution: Replace parts.