I can bet its the steering stabilizer. Chrysler is really dragging there feet on this, it should be a recall. So if it's still under warranty, take it to dealer and tell them you want a new steering stabilizer. If not get one from a jeep store like quadratec or whatever, this should fix the problem. It will only get worse, when you hit certain bumps in the road it sets if off. The problem wont just go away. The only way to make it stop is by slowing down. Don't let your wife drive it anymore until you get it fixed or figure it out, it's very dangerous.