Decel fuel cut (injectors completely off) happens under some closed throttle conditions. What conditions depends on PCM programming. Typically, coolant must be above a certain temp (engine mostly warmed up), IAT above a certain value (often doesnt enter decel fuel cut for VERY cold IAT), and RPM above a certain value (very roughly 2000 RPM in many cases). As RPM drops during a coast down, decel fuel cut stops at a given RPM value, like maybe 1500 RPM or so, and injectors turn back on.
05 Taurus SEL Duratec - my daily driver
04 Taurus SES Duratec - wifes car - TOTALED
06 Taurus SE Vulcan - wifes new ride
95 Taurus GL Vulcan winter car
Toy #1 - 86 Tbird 5.0 (original owner) - LOTS of mods
Toy #2 - 88 Tbird Turbo Coupe - LOTS of mods
67 Honda 450 Super Sport - completely customized