Engine Mechanical problem
2002 Ford Focus 4 cyl Front Wheel Drive Manual 85000 miles
My Ford Focus started missing and bucking, took it to shop, they replaced plugs wires, all ok for a short time. Samething happening, shop says valve is stuck and needed replaced $200.00, once they had the head off they called and say the "seat" fell out and now I need to buy a new had 1200.00. Can this happen? Can they rebuild the head or buy reconditioned?