I am having similar problems:
I replaced my computer. New install for everything. The Islander BN-2T seems ok. The BN-2B has no vacuum at engine idle, 15" at full throttle. both engines are same. At idle the carb heat left engine is full scale "4" and the right engine card heat is a "1". The plane has very little power and flys at best at about 100 knts. I have tried re-installing a couple of times and then downloaded again the compressed file and started again. Nothing changes. I have flown this plane for hours and I know what is normal and this is not. In real life I would expect both engines need a rebuild. While building the new computer I was offline for a month or more. Was there some sort of software upgrade. For a year or more the plane flew without a single problem. I fly a Cessna Skyhawk and I fly the islander turbo and see no problems with the engines or instruments. Help!