It is generally not recommended to put gas in a running car. This is because there is a risk of fire or explosion due to the gas vapors being ignited by the spark from the engine.

It is recommended to turn off the engine and wait for it to cool down before refueling. Additionally, turning off the engine helps prevent damage to the fuel pump and other components of the fuel system, which can occur when the car is running while being refueled.

It is important to always follow the safety instructions posted at the gas station and to be mindful of potential hazards when handling gasoline.