hi when i had trouble with my injector the heater light on the dash was flashing and went into limp mode we called the AA out who put a diagnostic test on it, and it came up with a fault code number no 4 injector did yours have the heater light flashing. all the fault code numbers are the same on the mondeos, so the garage is bound to come up with these now. maybe they jumped the gun on saying it was injectors, as they always fail.