Looks like VA may be part of the govt reformulated fuel mandate, which bans MTBE and uses 10% ethanol instead. Here in MA gas stations have to display a yellow sticker that states fuel may contain up to 10% ethanol. MTBE has been banned in MA. I saw a drop in my mpg by about 5% since the change over. Check out the link on reformulated fuel.

http://www.eia.doe.gov/emeu/steo/pub/special/rfg2.html

hope this helps...