Is it normal for an automatic transmission car to jerk when the accelerator is released? What causes a manual transmission car to jerk when the accelerator is released?

The accelerator is one of the most important devices for controlling the entire car. You need to step on the accelerator to start the car, and release the accelerator for operations such as deceleration and shifting gears. When you release the accelerator, the car occasionally jerks. What could be the problem?

Is it normal for the car to jerk when releasing the accelerator in an automatic transmission?

There are many reasons why automatic transmission vehicles jerk when you release the throttle, and most of them are normal. Because the vehicle's driving status and the driver's operation are uncertain, the automatic transmission can only maintain smoothness as much as possible, but it cannot guarantee that it will be abnormally smooth at all times.

For example, when the transmission is about to shift gears while driving, the driver suddenly releases the accelerator when he finds something wrong, which will make the transmission dumbfounded and cause a strong sense of frustration. It is also easy to falter when the car is cold, because the automatic transmission shifts gears with the cooperation of the engine. When it is necessary to shift gears, the transmission control system will communicate with the ECU, and let the ECU reduce the engine torque to cooperate with the shift to ensure smoothness. When the car is cold, the transmission oil pressure control and engine torque control are not as accurate as when the car is hot, so faltering is also normal.

Therefore, occasional jerking of an automatic transmission is basically not a malfunction. However, if it jerks frequently, then there is definitely a problem, and there are many reasons for this. Problems with the engine control system, transmission hardware problems, and sensor failures can all cause jerking. At this time, it is best to do a comprehensive inspection to eliminate the problem.

What is the reason for manual transmission car to jerk when releasing the accelerator?

In the past, manual transmission vehicles that used cable-type throttles were most likely to experience a sense of jerkiness when the throttle was released while driving in a low gear.

There are two reasons. First, the cable-type throttle valve closes synchronously after the accelerator is released. The engine stops spraying fuel immediately and is dragged by the vehicle to rotate. This is what we often call engine braking. This braking force is the primary cause of stalling.

The second reason is that the lower the gear, the greater the engine braking force, the stronger the sense of frustration, generally 1st and 2nd gears are the most obvious, 3rd gear will have frustration at higher speeds, not obvious at low speeds, 4th and 5th gears basically have no frustration. This sense of frustration is a normal mechanical characteristic, usually experienced drivers will slowly release the accelerator or release the accelerator while pressing the clutch when driving in 1st and 2nd gears, so as to avoid frustration.

Many manual transmission cars now use electronic throttles. When you release the accelerator, the throttle will not close immediately but slowly. This simulates the action of an experienced driver slowly closing the accelerator, greatly reducing the sense of frustration. If this type of car has a throttle release, it is mostly a cold car state, and it will return to normal after the engine reaches normal operating temperature.

Some manual transmission cars have more advanced control mechanisms. There is a switch on the clutch pedal. If the driver does not step on the clutch and releases the accelerator, the ECU will not only slowly close the throttle but also delay ignition to reduce torque, minimizing the sense of frustration. If the driver steps on the clutch when releasing the accelerator, the above operation is not necessary. The ECU will quickly close the throttle to save fuel. If there is a problem with the clutch switch of such a car, the ECU will misjudge that the driver has stepped on the clutch when the accelerator is released, and will directly close the throttle, which will cause strong frustration.

How to control the throttle while driving

The correct posture for stepping on the accelerator

We use our right foot to step on the accelerator, with the right heel as the fulcrum, and step on the accelerator by rotating and driving the flexion and extension movement. When stepping on the accelerator, try to step lightly and lift slowly. During the stepping process, the heel cannot leave the ground and still needs to be in contact with the ground.

It should be noted here that you cannot drive while wearing slippers, high heels or thick-soled shoes, as this will interfere with driving operations.

Tips for controlling the throttle

Before the car starts, the accelerator cannot be pressed too low. At this time, you can lightly press the accelerator first, and then slowly increase the force. After the car speed increases, you can maintain the force, or reduce it appropriately.

When the car is driving, the accelerator pedal should be stepped on according to the road conditions at that time. It is best to increase or decrease the accelerator pedal slowly and change the speed slowly.

When the car needs to brake, the sole of the foot needs to leave the accelerator, and use the heel as a fulcrum to lightly step on the brake to achieve the effect of reducing the speed of the car.