After cleaning, the engine compartment shakes at idle speed or low speed.

When the vehicle is started or stopped without turning off the engine, if the body is found to shake obviously, it may indicate that there are three situations in the vehicle: 1. The most common cause of vehicle jitter caused by serious engine carbon deposition is that the throttle valve is too dirty or the injector has too much carbon deposition. 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 problems Check the working conditions of spark plugs, high-voltage lines and ignition coils. Poor ignition system and poor spark plug misfire can also lead to such failures. 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 the engine carbon deposit has been cleaned, the throttle valve has been cleaned, the oil pad and spark plug have been replaced, and the body is still 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 value of the intake pressure sensor is wrong, the car body will shake. Solution: Check the oil pressure and replace parts if necessary. 4. The aging of engine parts. 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.