if there were any addons that could increase fuel economy, the manufacturer would have put them on. they really do know how to build vehicles. addons may increase power or noise or ability, but they all end up losing in fuel economy.
unless you want to put some aerodynamic addons
post your fuel economy or do a search, there's lots of posts to compare with.
I disagree with this general statement....so if you will follow me on my fairy-tail scenario..
Fact: When I work near/at Fort Mac, I get noticeably better fuel economy then around Calgary. Fort Mac is also quite hilly, perhaps not as hilly as Calgary, but it is definitely not a flat landscape. Calgary Airport is 3553 ft above sea level. Fort McMurray is 1214 ft above sea level.
Theory: I have read that for every 1000 ft increase in elevation you loose ~10% of your power. A 200 hp engine will lose 20hp at 1000ft, and additional 18 hp at 2000ft, another 16hp at 3000ft, and another 7 hp at 3500 ft. In Calgary, a 200 hp engine makes ~139hp, but that same engine in fort mac makes ~180hp
Jeeps are severely underpowered, no one will argue that, however if you add forced induction (enter fairy-tale land) you first somewhat negate the 10% loss per 1000 ft as you are now pressurizing the engine, plus you add over and above. A normally aspirated engine is much more efficient at sea level vs higher elevations.
The stock 4.0l powerplant is starved of air in the Calgary area. If you supercharged/turbocharged your engine, you would see gains in mileage, provided you maintained your driving style, i.e, a hill you drive up at WOT and can only maintain 45mph, that same vehicle with double the power will pull that same hill at 45mpg burning much less fuel as it is working at a much lower rate of work..
Perhaps thats not a good way of explaining it. It was explained to me once like this, if you have a box that weighs 25kg, you as an 18 year old could carry that load much more comfortably and likely haul that load further than yourself as a 13 year old (unless you're benjamin button) because you are a much more powerful person.
The problem with my argument is there are not a lot of blown jeeps in Calgary (that I know of anyways) to compare.