There is a slight intermittent jitter when the car is idling. Is the throttle dirty?

There are many reasons for idling jitter. The most obvious thing is that the throttle valve is too dirty or the fuel injector has too much carbon deposit, which makes the mixture too thin during cold start and difficult to start. If it is determined that this is the case, the throttle valve or injector should be cleaned and the oil circuit should be cleaned at the same time. Secondly, there is something wrong with the ignition system. Too much carbon deposited in the spark plug will cause the ignition system to work badly, so the whole vehicle will not work well. Therefore, it is necessary to clean the spark plug with carbon deposit. Although it will shake when driving, because the vibration of the car body is relatively insensitive, especially the hydraulic feet used in many German cars, the shock absorption effect is better, but the service life is relatively short.

Air intake system, check the throttle and idle motor (some models do not have idle motor), and check whether the intake pressure sensor and air flowmeter can transmit normal working signals to the vehicle ECU (vehicle computer). If it is a slight jitter, it is normal. Don't panic. If it is intermittent jitter, the following problems need the attention of the owner for reference. Understand this logic first, and then explain what throttle is.

The spark plug has a lot of carbon deposition, which leads to serious ablation and poor ignition. Spark plugs are badly ablated and need to be replaced. Those with carbon deposits can be cleaned and reused. For example, whether there is serious carbon deposition in the combustion chamber, throttle and other parts, whether the engine foot glue is aging, whether the engine control system is misfiring, poor line contact and so on. , need to investigate one by one. First of all, the function of the throttle valve is to control the air intake of the engine by adjusting the opening angle of the damper. When idling, the engine speed is low and the demand for air intake is small, so the throttle opening is relatively small at this time. As a result, the intake air flow is constantly changing and the mixing ratio is constantly changing, so the engine speed will suddenly change, and the speed change is too sudden, giving people the feeling of intermittent jitter.

Another possibility is that the failure of the throttle position sensor can also lead to engine idling jitter, even low speed driving, which requires replacing the position sensor or throttle assembly for maintenance. Moreover, there is almost no solution to this kind of congenital jitter, which is more common in new cars or quasi-new cars running for thousands of kilometers. Unless the manufacturer upgrades the engine warm-up control strategy, there is no other way to solve it!