I have been fighting this monster for a while. The car will at first go into reverse then D4, but if you go back to reverse, I lose all movement, all gears. I have no D4 light but the bulb checked out good. I changed the ECU and the TCU because the outer casing looks like water has been in them. I currently have a code 43 for a fuel related problem.
Has anyone had this problem and know where to go next?

 

Might need to check the wiring and associated connectors for water damage as well.