whenever i come off of raised driveways or uneven streets the car makes a sweak/creak sound on my 96 GL. Ive narrowed it down to either the motor mounts (mechcanics assumption) or something with the suspension.
Sounds to me that it would be suspension related based on what you've described about going over uneven surfaces when it makes noise. Does it sound like it's coming from the rear or front of the car? Either way, it could be the sway bar bushing causing all the squeaking.