MPG update

I just completed my fifth tank at 87 octane.

Tank 1 - 26 mpg (90% highway)
Tank 2 - 21.2 mpg (50/50)
Tank 3 - 25.5 mpg (95% highway)
Tank 4 - 23.5 mpg (75% highway)
Tank 5 - 24.2 mpg (75% highway)

Average - 24.1 mpg. This is actually pretty good for a fairly heavy, powerful, AWD car in cold temperatures on winter gas. Apart from this past week of freakishly balmy weather, most of this driving has been in below-freezing temps. It's not much worse than the ~26 mpg I averaged in my Focus ST.

I absentmindedly put in 87 today, so I'll start the wash-out tank on 93 octane next, and then do five tanks at that level. Unfortunately for this test (fortunately for everything else) the weather is warming up much more rapidly than expected, so this comparison may not be completely fair. Also, a significant portion of tank 3 was in severe heavy snow and the AWD system was likely engaged more.

The car's own fuel economy meter is surprisingly accurate. After each fillup I've been zeroing out the meter, and typically it is only about 3% optimistic.