My Lifetime MPG indicator on my 2015 Outback is now showing 47.8 lifetime miles per gallon. Obviously I have never approached this even for one tankful. I just took it in for an oil change and Wilkins Subaru in Glen Burnie told me that this was entirely possible to get this MPG rating. His words were remember it registers all those times that you are going downhill and not giving the engine any gas and the computer may be registering it as 99 miles per gallon. I guess the service manager thought that I didn't have to give the vehicle any gas to get up that hill. He said that since it wasn't a driveability issue, Subaru probably won't fix it. This was not the answer I was looking for. My Lifetime MPG indicator went haywire around 9200 miles. I now have 12,600.

Lifetime monitor of gas mileage not working properly. Over the last 3 weeks, the gas mileage reading keeps going higher and higher, even though the mileage on each tankful has been lower than the lifetime average it displays. For example, I was averaging 28.6 mpg for the lifetime of the vehicle, and now the display says 34.6 mpg for the life of the vehicle. I've NEVER gotten that kind of mileage, and all winter I was only getting around 20 mpg. I think the computer has forgotten to figure in all the gas I've used over the past 3 weeks, but it HAS been adding in the miles I've driven; hence, the increasingly ridiculous lifetime MPGs. Everything else seems fine, and it's a fantastic vehicle. I suppose I'll have to take it to the dealership for an analysis.