Gas question regarding jeep wrangler unlimited rubicon, and locking axles?

[H20polo]

I drive a 2005 wrangler unlimited rubicon, I just got it and it is consuming a ton of gas even considering the lift kit and 35's. The light on the axle lock is broken and after asking around to jeep Buddies of mine I realized it was on for about 200 or so miles, I have since turned it off, but was this why I was gettin the terrible gas mileage?? Thanks