We had a simmilar story with a 4yr old Corolla some years ago. Oil light started flickering / tappety sounds, typical low oil pressure symptoms. Turned out an oil change was missed & engine was sludged up. Toyota wanted £5k to fit a new engine, what annoyed me was that they just expected me to give them the nod, "Shall we drop a new one in then ?" was literally what the Toyota oink said on the phone.
Day in the garage, sump-off, rocker cover-off, Forte engine flush run through for an hour & was as good as new, oil pressure right up to spec.
Car ran without fault for another 30k till we part-exed it.
Take it to a real garage, ie: not a Ford dealer.
If its compressions are ok, oil pressure ok, no knocking etc, then a good flush through might just save it. The technical guy at Forte was a mine of info, the stuff is trade only so you'll need to buy it through a garage.