03 focus SE Wagon, Automatic Tran, has a bit of a problem. Whenever it gets driven through a puddle (big, small, paddling pool, etc.) it will make this high pitch squealing noise, and then when it gets shut off after driving through said puddle, will have trouble starting. (It will turn over, catch, run for .2 seconds & then the engine will cut out, but all the electronics will work) THEN! if you can get it started, it needs to be reeved constantly or it will stall when it idles. Lastly, if the conditions are ridiculously horrible, & you need to go some place, you have to ‘2 foot drive’ the little beauty to whereever you’re going.
Now, she’s been in to see the Ford mechanics and has ‘stumped’ them. And me being the little internet person I am suggested a couple of things and they shot them all down. SO! Who’s got an answer for me? 
Are the splash guards missing? Sounds like belt squeal from the water. As for dying maybe water is getting into the alternator.
Splash guards are still there and not cracked.
Squeal is the serpentine belt and/or belt tensioner.
Running issue is classic bad plug wires and or carbon tracking/cracking on distributor cap (if it still has a distributor) and/or ignition coil(s). Pop the hood at night(or in dark garage), see if you can see sparks arcing around plug wires/boots, coil, cap etc. Can use a LIGHT spray of warter from a spray bottle to promote arcing, will show weak/bad areas.
You need a mechanic who gives a hoot. This is just classic water splashing around where it doesn’t belong. The problem is that fixing it will not likely be a big money maker. So you need a mechanic who actually cares about fixing cars for folks. Some are still around though they get harder & harder to find.
The the best of my knowledge, the answer is 42 - but its still the case that no one knows the question. And a good thing too.