Dose anyone get more than 10 mpg in 1989 jeep tj?
6 cyl fuel injection

I have a 1994 Jeep GC 4WD 6 cylinder. I get 21 or 24 mpg highway. Mine is a much heavier vehicle than yours. I don't drive over 55 mph either as if I go 60 or 65 I drop down to 17, 18 or 19.

Gas mileage for your vehicle should be around 18-20 MPG. Of course this is dependent on a few things like your driving style the state of repair of the vehicle and whether there are modifications like large wheels and tires.

Twinkiedooter is correct when he says that driving over 60 will considerably effect your mileage.