1996 Jeep Cherokee front end vibrates, jumps when riding on

This problem has been going on for about 2 months. We have since replaced the steering stabilizer and put new tires on it. When driving, if you hit a dip in the road, or like when going on or off a bridge, the whold front end shakes, jumps, sometimes into the other lane. It's like when you jump and land on your feet, but your knee gives way. It kind of wobbles, then after you almost stop, it will roll fine until another dip, bump.