If it has a sunroof there may be a drain hose leaking. On our 97 LS the drain hose can be seen if you remove the passager kick panel and look above the computor. The drain tude discharge can be seen up inside the wheelwell - you may have to remove the innner fender cover (I don't remember). The discharge had a little bit of stuff blocking it. We also resealed the cowl cover using black silicone. You have to remove the wipers and a bunch of clips etc. to remove the cowl cover (at base of windshield) - clean the cowl area drain paths. I'm not sure which one of these fixed the water leak, but after doing them it has been bone dry.
