What's wrong with the new car after 500 rpm and 900 rpm?

This situation is generally caused by the excessive opening of the throttle.

This situation is generally caused by excessive throttle opening, which is generally caused by carbon deposition in the throttle. I suggest you go to the repair shop to clean the throttle valve and get a computer. After cleaning the throttle, the speed indicator does not fluctuate up and down after starting, and it is stable between 700 and 900, with strong acceleration and reduced fuel consumption. It seems that the throttle valve is dirty.

Influence of vehicle speed on vehicles.

The rotational speed of an automobile engine is related to the number of times of work done per unit time or the effective power of the engine, that is, the effective power of the engine changes with the rotational speed. Therefore, under a certain engine effective power, there is a corresponding matching speed.

It is recommended to check the intake part or pipeline, check the throttle body including sensor, check the water temperature sensor, check the fuel injector and ignition part, and check the accelerator pedal and sensor.

When the speed suddenly rises, it means that it is inconsistent with the actual power. Simply put, it is to increase the fuel injection. At a certain speed, ECU will give the appropriate fuel injection quantity according to the collected data. The collected objects are generally based on throttle opening, water temperature, air intake and so on, and the correct fuel injection time and fuel injection quantity must be obtained.