Despite what many people will have you believe, there aren't that many ways to improve gas mileage, and increase power in your Jeep Wrangler JK - but one of the best is to add a JK air intake. This will replace the restrictive factory air box with a larger diameter tube with gentle curves that will bring more cool air into your engine. By introducing more air into the engine you'll allow it to breathe better and produce both more power and fuel economy. Jeep air intakes are even more effective when paired with a new JK exhaust system.
