Land Rover Repair: Range Rover Stability, land rover dealer, air shocks

Question
I Recently purchased an 04 range Rover with 88000 miles. While driving around town it rides great. Out on the highway it is smooth until the surface changes or when hitting a bump. All of a sudden the vehicle sways from side to side dramatically. Sometimes to the point i have to grasp the steering wheel tightly for possible need to over correct. I have taken it to Land Rover and they found nothing. they checked all suspension parts including air shocks (so they say). But, this cannot the correct. I feel unsafe driving at highway speeds. I have read other somewhat related questions, but i just wanted to piont out my particular experience. Any Advice?

Answer
It certainly sounds like you have some loose parts in the front end.  If that particular Land Rover dealer did not have the skill to find the problem perhaps you should try another one.  Often shakes like you describe are the result of collective wear in a bunch of parts.  So there is no one "smoking gun" to find.  Instead, you have a bunch of slightly loose pieces and the total of all the free play is what causes the problem.  The fact that there is no really loose part can deceive someone who does not understand this.

Tire balance will also trigger this, but the problem is invariably related to suspension wear as well.  In a 2004 Rover the situation is complicated by the fact that the rear suspension wears too, so there are more places to look.