Re: Poor gas mileage on 05 Taurus
the sho was discontinued in 99. you either have a Vulcan push rod or duratec engine and 23 is a little low but not bad. it depends on actual speed, tire pressure, and if stuff like the air filter and fuel filter has been changed.
go around the car and check tire pressure, and pop the hood change air filter, if it hasnt been a year dont worry but if you dont know change it. if you dont know when the fuel filter has been changed change it too.
also fuel economy drops big time once you reach 55 mph with the biggest notice after 65 mph use your cruse control it will lower gas consumption.
i am going to assume on i 10 you were doing 75-80 if you could. that would do it right there.