The so-called overrun cut-off is an interruption of the fuel supply in a petrol or diesel engine.
This primarily serves to reduce fuel consumption and improve emissions.
A modern engine does not consume any fuel when coasting.
But why should you deactivate the fuel cut-off?
That can have several reasons.
On the one hand, this produces the so-called overrun popping, on the other hand it is possible to maintain the boost pressure in a turbo engine with a deactivated overrun fuel cut-off.
This is also known as anti-lag system or bang-bang system.