[pollitt]

Hi Zack, a few thoughts....
1.The water ingress may be due to the filler cap seal not fitting correctly and the rubber cup that sits around the filler may have a blocked drain hole?? A small cable tie will safely clear it.
2. The fuel shot-off solenoid may be at fault (or the power supply to it). It sits in the pump at the front of the car, between the engine and the radiator, immediately feeding the injectors. The solenoid is on the left, try cleaning the connection. This is fed from a relay near the nearside suspension strut, also a possible problem.
The solenoid itself can be bought from any good bosch agent but sounds like you may have a spare one anyway now!

Good luck
Al