mazda 2002 protege was jurking and smoking took it to the shop and had the

[LatoyaR]

catalic converter replaced as well? mazda 2002 protege was jerking and smoking took it to the shop and had the catalic converter replaced as well as the exhaust pipe and the car still jerked and would slow down. Now it wont start. The mechanic stated it was leaking oil and the engine would need to be replaced is this true what to do