[Turbio]

So I just filled up my new '13 OB with regular and I'm noticing a significant fuel economy ding compared to the tank my dealer delivered it with. I'm noticing much lower fuel economy at any kind of load. Is that to be expected with regular? I'm assuming it's because they filled it with midgrade and I refilled with regular, but does this square with what anybody else has noticed?

 

[Green LTD]

If they filled with straight gasoline and you used an ethanol blend that could account for the difference. Winter blend gas also takes off a little mpg.

 

[1 Lucky Texan]

might take a few drive cycles for the knock sensor to adjust the spark advance/retard but, that seems like a big hit to me.

 

[gls]

Since your outback is designed for regular there should be no difference. Driving conditions and air temperature are more likely causes. 10% ethanol would reduce mileage only 2-3% when compared to pure gasoline. You may also notice very high idle speeds and high engine speeds with the CVT in cold weather when warming up (if you leave the heat/defroster off you'll see much lower RPMs). This could also account for the mileage difference.

 

[there4igraham]

I'd check your tire pressure and make sure it's correct. Are your cross bars stowed because those create a lot of drag when they're in use? Have you added any exterior bits like a bra, bug shield, or window vent covers?

If you haven't done any of the above and your tires are properly inflated you could simply run your tank down to just an 8th of a tank left then fill it up again at a different gas station with regular to see if you just got a bad tank of gas. Any fuel grade difference would be negligible unless you were putting ethanol in it which would result in a pretty substantial drop.

 

[AWDFTW]

Your 13 calls for regular, there is no reason for the dealer to fill it with anything else.

My guess is conditions or perhaps a difference between pure gas and E10 gas.

 

[upflying]

What calculation method are you using to determine the mpg loss?
BTW, a typical new car habit is to raw egg the pedal a bit to allow for a proper break-in.
As the newness wears off, you mash the go pedal more and lose some mpg.
90% of what folks say they get for mpg is caused by driving habits.

 

[p nut]

Dealers would be stupid to spend extra money on anything other than regular, since that's what it calls for. With MPG, you really need several fill ups to get a better reading. I've had MPG figures jump dramatically one tank to the next, as there are many variables. Method of calculation, as upflying mentioned, is very important as well.

 

[mikelipke]

Mid-grade fuel in that car will gain you nothing in mileage, or anything else, really.