This may or may not help, but I can't resist telling my story:

Last summer, my wife and I and our two teenagers went on vacation in our
2000 Malibu. We left Nova Scotia, travelled through New Brunswick, Quebec
and stopped to visit family in Ontario. We then headed south, crossed into
the US at Niagara Falls and headed east through New York, Massachusetts, New
Hampshire, Maine, crossed back into Canada at New Brunswick, then headed
back home to Nova Scotia.

My point of this story (yes, I do have one!) is that just before the
mid-point of this trip, the car developed an ominous knock in the front end.
It didn't happen every time, but even a slight bump or dip would cause a
quiet, but obvious "clunk". When we stopped to visit in Ontario, I borrowed
some tools and assistance from my dad and we started the search. We
inspected the struts and mounts (my initial guess), checked the bearings and
joints, removed the wheels, brake assemblies and generally gave the entire
front end a thorough examination. We could find nothing wrong, yet when we
re-assembled everything and I test drove it - the "clunk" was still there.
Since we could find nothing obvious that would render the vehicle unsafe or
unreliable, I convinced my wife we could continue the trip. All through
Southern Ontario and Eastern US, that damn knock haunted me - I turned up
the stereo and tried to think of something else. My wife, assured that we
were in little danger of crashing or being stranded, promptly dismissed the
noise and enjoyed the scenery. I, on the other hand, was slowly being driven
mad. Each "clunk" was like another slap in the face - another reminder that
not only was my machine flawed, but that I was incapable of fixing it.

We arrived home safely after a week of excellent vacation despite the
"clunk" and the very next day I got to work on the car. I was determined to
fix the noise or die trying. The first step had to be cleaning out the
assorted clutter, garbage and souvenirs that tend to accumulate during such
a trip. While working on the passenger side, I saw a half-empty water bottle
under the front seat. When I jammed my hand in to retrieve it, my fingers
slipped off and the bottle rolled forward. When it hit the underside of the
seat's structure... you guessed it - "clunk". I tried it a couple more times
to be sure, but there was little doubt now. The noise that haunted me in 2
nations, 4 provinces, 4 states and thousands of kilometres of highway was
caused by garbage! I sat in the driveway with the bottle in my hand while my
emotions ran from relief at finding the cause, anger at not finding it
earlier and finally acceptance that sh*t happens.

Thanks for letting me tell my story and good luck finding your noise (don't
forget to check under your seats!).

Wes