Water and ignition stuff don't get along. Sounds like some water might have gotten into the distributor cap.
Has the car dried out and does it run well now?
Water on floor could be leaking from either through the floor boards, looking under the car do you have holes in floor boards?
Could be leaking around windshield and running down to floor. Clogged drains could also contribute, sun roof drains, or maybe got in through air intake for HVAC system (not sure if this could happen). Maybe even weatherstripping around door is leaking.
Hope this helps some.