annoying rattling!

hey i have an 89 crx si.
anyways, iknow this may be different depending on the condition of the car, but, i have an annoying little squeak or rattle from the inside of my car, by the trunk. if i'm on a smooth road, my car is so quiet. i hit some bumps or drive on a piece of gravel or something and the little annoying squeak comes. i tried sitting in the back, when my dad drove to see if i could find it, but i couldnt :(
so help lplease!

well my hatch used to squeek. i ended up replacing my hatch seal and that went away. if this is the case with you, you can put some vaseline of grease on the hatch seal temporarily. also shove some grease into the hatch latching mechanizm. give those a try man, thats about the only squeeking ive ever had.