Eaves1

Hello,
My standard 02 civic, will crank for days but will not start. The green immobilizer light is flashing and I can't get anything to.connect to the ecu.
My girlfriend was driving it and it started to buck and kick so she pulled over and shut the car off. At that point the light started flashing and it would not start. Then after it was towed home and sat for a bit I tried it again. And it started. About an hour later it was back to the same thing and has never started again.
To begin here is everything that has already been done to try and correct the issue,
All new grounds put on and cleaned up.
All fuses checked and replaced.
Both main relays are replaced.
Replaced the ecu, Imob. And key all mathing out of the same car with the same code.
Checked timing.
Had two different people try to program the keys again with no success since nothing can connect to the ecu.
I'm out of ideas on what to check next on the car. Any suggestions would be appreciated.