Some 2015-2018 Focus ST vehicles may exhibit MIL On with DTC's P0300 and/or P0316 store in Powertrain Control Module(PCM) memory. Vehicle may also exhibit perceived misfire after cold start until Engine Coolant Temperature(ECT) reaches 49 degrees C (120 degrees F) Install (4) new CYFS-12-YEC spark plugs and set plug gap to 1.0mm(0.040). Use ROTUNDA RTTP tool KDT165 or equivalent to gap and adjust the plugs before installing. For Drivability concerns Refer to Powertrain Control/Emissions Diagnosis (PC/ED) manual. Engineering is currently investigating this concern. To assist with the investigation use the Report A Vehicle Concern link at the bottom of the Oasis report and submit a Global Concern Report (GCR). Continue to monitor OASIS for updates.