I would say that if you are doing 10-12mpg, then it can be improved. But if you are in the 15 range, you better be looking for some downhills to coast on. Air up your tires, go with bigger tires (but stay narrow), tune up, desmog if you can in your state, get a carb rebuild. I don't think a K&N will be the magic bullet; you probably will not tell the difference.
Fuel economy is not the strong suit of these trucks. Either get accustomed to "bad gas mileage" or get a small commuter to knock around in. Outside of a normal tune up, there isn't anything else to do. If you have much of a work commute, an FJ60 is not the car for you!
Hahahaha i just got the mental image of a 5000 pound cruiser flying off into oblivion when the wind hits the sail just right. Id put a little chair up top and get a buddy to sit up there and work the sails.
10mpg in town and 12mpg on the highway going an indicated 55mph (really about 65mph). 33's and 2.5" lift and no roof rack. FJ60 (non EFI and no overdrive) with 135K on the clock. I haven't given it a tune up in nearly 15K miles... probably time.
4500lb bricks just don't get good gas mileage . But they can go anywhere and can haul lots of stuff.
I consistantly get 14mpg city and around 16mpg hwy. That is with the car completely empty (just myself), tires aired up to the max, headlights are off and so is the blower fan. This is with stock 235/70R15 tires, old igntion components, and a bad alignment. I'm hoping to get better fuel mileage as soon as I get my new 235/85R16 tires and fix the toe out.
My girlfriend's Jetta TDI of course gets much better mileage!
The key to getting great mileage with a 60 is to have a neighboor without a locking gas cap. It was amazing I went from 12MPG to almost 30 MPG. I just do 5 gallons a day, so he will never notice. His mechanic can't figure out why his new fancy smanchy truck is only getting 8-10 MPG.
After a recent tune-up, Jim C. carb rebuild and replacing lots of smog equipment and vacuum tubes I'm getting about 17 MPG average running 31's, everything else stock. Not great, but it proves that 60's can do better than 10mpg.