Like any piece of machinery with a lifespan of almost two decades, Jeep's 4.0 liter straight six engine had good and bad years, separated primarily by an upgrade to the multi-port fuel injection ...

The JK era also saw the end of the line for Jeep's legendary 4.0-liter inline six-cylinder engine. This motor ranked eighth on SlashGear's list of the auto industry's most reliable inline sixes ...