Modern gas gauges do not change the level of fuel if a car or truck accelerates, brakes or turns. This is not because the fuel is not moving, it is because a computer in the instrument cluster or attached to the fuel pump is calculating the volume of fuel in the tank. In this video, Andrew Markel covers how the system sense and calculates the fuel level. This video is sponsored by Carter.
How do modern gas gauges stay still when the gas in your tank moves around? This video is sponsored by Carter.