Welcome to TRS
Manual or automatic?
All fuel injection computers have a "Clear Flooded Engine" routine
It allows driver to Crank the engine with fuel injectors OFF to dry out the flooded cylinders
"Clear Flooded Engine" is initiated by the TPS
TPS gets 5volts from computer
When throttle is closed TPS sends computer back under 1 volt, .69-.99v is spec
When throttle is wide open(WOT) TPS sends computer 4.5-4.9v
If RPMs are 0 and TPS shows 4.5-4.9v then computer starts "Clear Flooded Engine", fuel injectors are turned OFF, so crank but no start
So your TPS is shorted between the 5v and return signal volt wires, if the wires in the harness were shorted then unplugging TPS wouldn't allow startup, computer would stay in "Clear Flooded Engine" mode
Test TPS with OHM meter, top and center wires are the 5v and return, should show HIGH ohms with throttle closed, then low ohms at WOT
Stalling in water can be a few things
The Cold air intake is in the rad support and lower down behind the grill, if you hit the water too hard you can suck in water spray stalling engine, check air filter box for moisture.
If water level is too high the Fan can spray the inside of engine bay causing electrical issues
The Starter Relay(solenoid) on the inner fender is the Power distribution point for the vehicle, one post will have battery positive cable and several other wires attached for all the electrics, all wires here need to be in good condition.
One wire from this post runs to engine fuse box, its the main power for ignition switch, so a problem with this wire cuts power to engine systems which gets it power from ignition switch.
There are two Relays in the engine fuse box that can stall the engine
PCM relay and the Fuel Pump relay, these are activated by ignition switch
Do you remember if the CEL(check engine light) came on when engine stalled?
It should if computer was still getting 12volt power
If no CEL then power was cut to computer which is why engine stalled