my car, which believe it or not, had a similar problem, a big knock when i went over bumps. this is shortly after i put the sway bar on. I did not have the nuts that hold the bar to the end links on tight enough. with a small 14mm wrencha and an allen key, it was tough, but got some different tools that helped. gotta have it tight. check that first like Jeffy said.
i couldnt hear the sound of the sway when i pushed on it, because, you can never push that suspension when it is resting, like a bump on a road at 45 mph. so that why it is so hard to simulate while not moving. that my exp. with another vehicle, but i think it still applies.
