I finally go serious about my TJ Jeep Wrangler's fuel economy and decided to do something about it:
So I sold it and bought a Suzuki Jimny
The latest Jimny is still exactly the same size as the US market Samurai of the 80's-90's. It's virtually identical in size and interior space to the TJ Wrangler, if you exclude the Jeep's long bonnet to house that I6.
So 18mpg (mostly highway) became 42mpg (mixed), which should still increase once the car loosens up.
The drive experience isn't all that different, but the Suzuki is at least a little better in every way. The main improvement (after economy) is wind noise. The TJ (hardtop) would howl at 30mph and get worse from there. Since you have to drive highway miles to get to the off roading it made the whole car a little pointless. The Jimny is still live axle at both ends, it it's at least livable. Driving the TJ, a bump at the front would seem to upset the rear axle too. The Suzuki seems to manage better despite the much shorter wheelbase.
Suzuki have done a stellar job of the newest Jimny. It's like an off road MX5 in that all the controls are perfectly weighted and positioned. It's light weight to the exteme, even the ECU is only about the size of a smart phone.
Plenty of room to work