2015 Lincoln MKC Reserve 2.3

Owned for many years and have enjoyed. Never missed a service and kept up with all maintenance. Booklet of records. Recently got a check engine light. Misfire in cylinder 3. Was told it needed decarbonized. Had brand new ford coils and spark plugs installed with injectors. Also had the engine decarbonized at a handsome some of money. The oil separator pvc replaced with new unit. Check engine light went off. But returned shortly after driving 30 miles with same code. ??????? Vehicle runs and drives and gets up to speed as before. No loss of oil or smoke from exhaust. No coolant loss whatsoever. After returning vehicle to mechanic they did compression check #3 cylinder had lower compression then other cylinders. Vehicle has now 1 year old high performance continental tires. Brakes replaced with new rotors along with front calipers. Interior in excellent shape and everything works. Panorama roof, clean leather seats, power everything, sat radio, mp3 and navigation, rear subwoofer, heated and cooled seats, ac blows cold, adjustable suspension, sport mode with paddle shifters on steering wheel. Led exterior lights and HD headlamps, Alarm, lane keep assist, accident avoidance system, cruise control with distant monitoring. Fully loaded awd suv. Asking $4250.