Some 2015-2016 Ford Focus ST vehicles equipped with a 2.0L GTD engine may experience an engine speed dip with or without the MIL on and/or DTC P2610 or P08B9 stored in the PCM.
Reprogram the PCM to the latest calibration using IDS release 99.02 or higher. Make sure that you are connected to the internet when entering module programming to obtain the latest updates.