Sudden change in gas mileage '08 Jeep Wrangler

since dec '08 when i purchased my '08 wrangler, i’ve been able to drive 240-260 miles per one tank of gas (18.5 gallons). since mid feb '11, i’ve only been able to drive 175-190 miles per one tank of gas.

driving habits and purchase of gasoline (87 octane & location/brand) have stayed the same.

First, you do really want to calculate gas mileage independently of your gas gauge. Fill the tank and note the mileage on your odometer or reset your trip odometer. Drive through several fill ups while keeping track of the # of gallons purchased. After several tanks of gas and right at the last fill up divide the miles driven by the total gallons added. After you do this the first time, find the basic EPA estimates for the Jeep and compare. Make sure to take into account the kind of driving that you do. At the moment you could just have a screwy gas gauge.

That said, if you want to maximize gas mileage make sure you keep up with basic maintenance - plugs, wires, filters. Check the air pressure in your tires regularly. Refer to the placard on your door pillar for the correct specs.

Any of those things out of line can noticeably affect your MPGs.

For any sudden changes - if you know they are real, you check for dragging brakes and you check your cooling system - thermostat and coolant temp sensor.

You’re not driving around with a check engine light on are you?

have no idiot lights on while driving…

thanks for the input…