There should be a big sign on thee window sticker of turbo cars: 93 octane only!!! I tried running 89 octane (mid-range) and mpg was 14 around town. Finally started running 93 octane and now my combined mileage is around 28 mpg. Manual only says engine won't run as well on less than 89, but doesn't say it will run much, much better on 93. The price premium for higher octane is worth it.

 

I just bought a 2014 Malibu LTZ. Thanks for the post. I will check my mileage also and add to thread.