What is the reason why the car will feel frustrated when it loosens the throttle?

It is very normal that any gearbox may have a setback when collecting oil. It is more likely to appear in automatic transmission. In fact, it is to collect oil and slow down the engine. When the gearbox is in high gear, the torque load is large.

However, when the vehicle speed drops, the engine torque drops synchronously, and the torque is insufficient for an instant, which causes the engine to be unable to accelerate, which is equivalent to a force pulling the engine backwards, so that the car will have a backward force when moving forward, and the natural consequence is frustration, so this is a very normal phenomenon!

In the automatic gearbox, releasing the throttle will trigger an upshift, and the system will think that the vehicle no longer needs power at this time, so it will trigger the upshift logic, so that the gear will rise higher and play a better fuel economy. After the upshift, the lower transmission ratio will depress the engine speed, which is not enough to maintain the current speed, which will naturally lead to frustration.

In fact, this has something to do with the logic of automatic transmission. It is easy to say that the engine itself is powerful enough. If the power itself is insufficient and the fuel economy is excessively pursued, it will be upgraded in advance, which will easily lead to the phenomenon of frustration after the upgrade!