Basically anytime you lift your foot from the gas pedal while moving (coasting) you'll enter fuel cut mode (the fuel injectors are turned off). ... When idling in gear (stopped) or neutral (stopped or moving with normal idle vacuum), a tiny amount of fuel is metered to keep the engine running.

Do fuel injector shut off while coasting?

If you're coasting in gear most modern engines will completely shut off the fuel flow. The transmission/gearing keeps your engine spinning and zero fuel is required so the fuel is completely cut until you either hit the gas pedal or the rpms drop below about 1500.

What turns fuel injectors on and off?

The amount of fuel injected is controlled by a flap valve located in the engine's air intake. The flap sits beneath the control unit and rises and falls in response to airflow - as you open the throttle, the 'suck' from the cylinders increases the airflow and the flap rises.