I'm getting an average of 22-23 mpg.  This is combined highway and city.

Al

If I'm getting 22.5 (highly repeatable) with my 230,000 mile 93 3.8 Tbird,
heavily loaded with tools and parts, in daily 100 miles highway, 25 miles
city; then I cant imagine why you would get much less unless you put your
foot in it a lot... I do about 3-4 WOT's a day merging, but about 20
startups.

I use Speedway gas exclusively.. and I highly recommend you do too if it's
a big seller in your area.  Bought at a high volume station, you'll
probably never have fuel system problems. {Empirical finding from out of
car injector testing and engine teardown}

Alternately... I have gone to praising BP instead of damning them (for the
previous 25 years).. I think the new formula is good.

I average 25.8 This is on mostly 35-40MPH secondary roads.