It has an EFI 5.7. 160k miles.

So it rained pretty hard here in Austin and the van was working just fine. Drove it around in the rain for two days straight, no problems. I parked it for a few hours, then started it up and took off down the street. It started cutting out when I hit a certain RPM and some of the cylinders wouldn't fire. The engine started shaking because only certain cylinders were firing and it was throwing it off balance. It idled just fine, but once I gassed it, it would get all choppy.

So I get he thing home, park it overnight, and try to start it in he morning. Won't start! The engine seemed to be turning over unusually fast and at some point in the turn over sequence, the engine would lock up (didn't sound like a mechanical lock up) and the lights would shut off in the cabin. So I gave it another day and went to try it again with a different battery. Same symptoms but now the lights don't cut off and the engine continuously cranks. Still no ignition though.

I Reset the fuel pump safety switch. I checked the fuel pump fuse and some others.. All good there.

Any ideas?! Please help, thanks!

 

Something you can check,
at the top of the engine make sure none of the plugs have water in the holes.
If water got around the PCM , might be a good idea to just unplug all the plugs you can see that might have had water run over them and make sure they are clean and dry.

 

Also check for water and condensation inside distributor cap.