Deceleration Fuel Shut Off (DFSO)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2019 Lincoln Navigator, 2019 Lincoln Nautilus, 2019 Lincoln MKZ, 2019 Lincoln MKT, and 2019 Lincoln MKC. However, it is still accessible from the selected car via links, so may be relevant.
During a DFSO event the PCM disables the fuel injectors. A DFSO event occurs during closed throttle, deceleration; similar to exiting a freeway. This strategy improves fuel economy, allows for increased rear heated oxygen sensor (HO2S) concern detection, and allows for misfire profile correction learning. One some vehicles with direct fuel injection, the PCM may also disable the ignition coils. This strategy extends spark plug life during the fuel shutoff events.