Down low on the right rear side of the engine is the Altitude Jumper Wire, a black and white wire with a large eyelet connector on it, hanging out of the wire harness. If you are operating the Jeep above 4,000 feet, you are supposed to ground this to the nearby bolt on the engine block, where you will see some other wires grounded. This tells the computer to make adjustments for the thinner air. At lower altitudes, make sure this wire is secured to a harness or some other insulator, and is not dangling where it might come in contact with a ground.