mcwllt12

I have a 09, 2.2, automatic. With 80% @ 35-45 and rest @ 60-70. My average is a steady 21-22 I'm using the low grade. As I was filling today, I looked to see if there was any indication of ethanol in the mix. Far as I can tell there isn't any. When my wife took LittleRed to Austin, the average was 35 mpg. I changed the plugs (they don't make them like they used to) and the air filter. After reading other posts, I guess it's not to bad after all. Still, I expect better milage.
Lots of variables. One key to better gas milage is to let the wife drive. Good for at least 1-2 mpg increase

donbrew

They make plugs better than they used to. The proper AC/Delco 41-103 are gapped at the factory and will last at least 100,000 miles.

The key to your lower MPG is the 80% part. When you are stopeed in traffic you get 0 MPG and that goes into the average.

LawDog88

x2 my OE AC-Delco's lasted me around 105,000 before changing. Put in the new, and runs like a champ again. Still passing more than a few gas stations.

Oldblue

I've got 76,000 miles on my second set of 41-103 Delco plugs and still average 32-33 MPG, we just drove it from here near Buffalo NY to Cape Cod put on 2,150 miles and the whole trip averaged out to 32 mpg and hit 36 mpg while cruising the I90 at 70 MPH. not bad for a 176,000 mile 2.2 L auto 2007

Doc brown

I average 26-27 in mixed city/freeway driving. And that's with 10% ethanol. You say your wife gets better mileage, and that speaks volumes. Driving style has a lot to do with mileage.