if you hollowed out your catcon (removed the shit inside of it) then you are SOL. a new cat for that is probably 400 bucks. if your plugs werent firing because of the water, then the engine was dumping fuel into the cylinders and it wasnt getting burned. the unburned fuel that the piston didnt push out on the exhaust stroke, plus you having to drive with your foot heavy on the pedal to keep it going probably started to seep past the rings into the crank case. also a bad MAP sensor will load the engine up to the point where it will barely run (excessive amounts of fuel). any decent tech should be able to hook up a scanner and check the operation of the map sensor and all other sensors in a short period of time. now, if the hood was off and it got dumped on then you might have water/condesation in some of your sensor connections, which in time would corrode them, but they are usually weatherproofed pretty good.