I am thinking you may want to look at the wireing harness and the elctrical connectors at the ECU.
If they were exposed to water and another ground helped the situation, the harness may have corrosion at the connectors or maybe a little more damage as far as damaged and corroded wories. It all depends where the water got to.
Try using PB Blaster or Electrical cleaner with a toothbrush at first and some fine emery paper if you see and corrosion.
You may have to replace some ends, Radio Shack is good for auto electrical terminals, because cleaning corodeded ones is hard and makes the fit loose.
Remmebr, you can remove each wire from a connector by using a dental pick kit, which will come in handy for this job, to push in tabs that hold each terminal. It can then be pulled on gently and the terminal replaced and put back into the connector. Make sure it, "Snaps" back into place as you may have to make sure it connects by hand each thime you connect it.
Sunday, March 25th, 2012 AT 4:00 AM