bgrebuilds

Morning All, I am trying to diagnose a problem that my parents are having with their Fabia. The car will every few days go into limp mode. Car wont go above 2K rpm. A local garage suggested that it may be a faulty injector on cylinder 1. When I plug an OBD2 readr into the car I get an error on cylinder 1 so I initially thought that they were right and we might have a bad injector. The thing that strikes me as a bit odd is that this is only happening every few days or so. the rest of the time the car runs perfectly. Has anyone had a similar issue and managed to figure out what the cause was. My parents are relucant to sink a load of money into buy new injectors if they don't need it. If anyone can offer any advise I would be very grateful. Cheers