I have the same problem on my 93. I have replaced the cowl seal, and went as far as clipping off the bottom of the cowl drain tube. I checked to see that the drain tube was working by pouring water from a pitcher into the cowl, and the tube drained fine (apparently not fast enough), but the driver side floorboard was still getting wet! I didnt dump a whole 2L in there all at once either. Looking down into the cowl, I dont see where it could possibly be leaking. And because of the pitcher, it has to be from the cowl itself cause everything else stayed bone dry.