The third-gen Jeep Wrangler JK entered production in 2007. This model is available with a more powerful 147-horsepower 2.4-liter four-cylinder engine. Combined with a new six-speed manual transmission, it is rated at 16/19 mpg. The extra gear is necessary to extend the highway range of the Wrangler JK.
The 4.0L AMC-based inline-six engine no longer available, Wrangler JK received the new 3.8L V6 engines that produce more power and torque. However, this move was not primarily intended to improve the fuel economy of the vehicle, but rather to compensate for the added weight. The 2007 Jeep Wrangler TJ Unlimited tips the scales at 4300-pounds, which is about 1,000-pounds more than the 2006 model. The new 3.8-liter V6 motor is good for 205-horsepower and 15/18 mpg when paired with the 6-speed manual, which is only a 1 mpg increase over its predecessor (the TJ).
The 2008 and newer models of the Jeep Wrangler JK saw the availability of an optional four-speed automatic transmission. Either way, fuel economy is still rated at around 15/19 mpg but choosing the rear-wheel drive option will give you an additional 1 mpg in highway driving.
When the 2012 model came in the market, potential buyers were rejoicing when Chrysler announced a new 3.6-liter V6 with 285-horsepower and 260 pound-feet of torque. The six-speed manual came standard while a new five-speed automatic is optional. The 2012 Jeep Wrangler Unlimited with the automatic is good for 16/20 mpg while the manual can achieve 16/21 mpg. The hike in power means a better power-to-weight ratio and consequently better fuel economy as well. This trend will continue with newer models that net a combined fuel economy of 18 mpg whether equipped with the manual or automatic.