Originally Posted by
Zar_1
As a pilot, if you had a similar issue during cruise, how concerned would you be?
Since the other engine will have to be operated at a significantly higher thrust setting to compensate for the IFSD, and it could also have similar vibration issues (since it's the exact same engine, probably with a very similar age).
Engine failure is Land ASAP. Make it to the nearest suitable. There's nothing more one can do.