I'm only getting 21-22 in mixed driving. I've got a 5 speed with slightly oversized tires (currently 235/75-15, door sticker states that OEM tires were 215/70-14) I drive about 10 miles on the highway and 30 on side roads for my commute and rarely get above 65 mph. I shift somewhere between 3-4000 rpm. And I run 87 octane. It's costing me $60 per week as it is
Also, I have fresh plugs and wires and a K&N air filter. I'm thinking I'm going to put some good injector cleaner through the system and change out my fuel filter soon.