1996 Buick Skylark -water, water everywhere!!!

Got a 96 skylark that just started running horribly.

Starts fine everytime, idles good. But when you give it gas it sputters and spits. All plugs and wires have been checked or replaced.

Right about the time this strted happening, I noticed quite a bit of water on the floor. I shop vacd it up and a few days later it was back. So I shop vacd it again and took the hose to it...no water was getting in anywhere I could find. I threw a tarp over the cab which covered about 2/3rds of the car. and whenever it rains my floors get soaked. Cant figure out where it is coming in but my guess is where ever its coming in (firewall) the cpu got wet and that is whats causing the problem. I no someone else who had a 95 skylark who had the same problem.
He got rid of his before fixing so hes no help.
Anyone havee this problem or know what it could be?

thanks.

All these N-body cars from 1992-1996 or 1998 had this problem. I have a '95 Skylark GS and I did all I could. Took the cowl off, sealed everything and no results. I finally just stuffed a towel where the firewall ends and the carpet begins and change it every week.