Is it normal for the engine to idle at D gear when releasing the accelerator?
3 Answers
It is not normal. The reason why the engine speed drops to idle when releasing the accelerator is due to carbon deposits causing incomplete combustion of gasoline, resulting in engine vibration. Below is an introduction to engine-related content: Energy conversion: An engine is a machine capable of converting other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (Stirling engines, steam engines, etc.), jet engines, electric motors, etc. For example, an internal combustion engine typically converts chemical energy into mechanical energy. Device: An engine can refer to both a power generation device and the entire machine including the power device (e.g., gasoline engines, aircraft engines). The engine was first invented in the UK, so the concept of an engine also originates from English, with its original meaning referring to "a mechanical device that generates power."
When driving an automatic transmission car, if you release the accelerator pedal in D gear and the idle speed stabilizes within the normal range, such as 700 to 1000 RPM, it is completely normal. I often drive automatic cars, and every time I release the accelerator, the car coasts slowly while the engine maintains a low RPM state. This is automatically managed by the Engine Control Unit (ECU) to prevent stalling and save fuel. The ECU adjusts the air-fuel ratio via sensors to ensure smooth starts. However, if the idle speed fluctuates irregularly or suddenly spikes above 1500 RPM, there might be an issue, such as carbon buildup in the throttle body or a faulty sensor. In such cases, it's best to visit a repair shop promptly. Overall, this operation is safe in daily driving, and there's no need to worry about the car shaking or losing control.
As someone with a basic understanding of cars, I must say that maintaining normal idle speed after releasing the throttle in D gear is a common phenomenon. The vehicle's ECU intelligent control system automatically adjusts based on RPM to maintain a fixed low speed, which both saves fuel and prevents engine stalling. This idle speed is typically around 800 RPM, and as long as the needle remains stable, there's no issue. However, if the idle speed fluctuates abnormally, it might indicate excessive carbon buildup in the throttle body or a faulty air flow sensor, which could lead to increased fuel consumption. Regular cleaning of the throttle body and inspection of related components can prevent such situations, avoiding minor issues escalating into major problems. From a safety perspective, smooth idle speed ensures driving safety, preventing sudden breakdowns in traffic.
