Thanks for the replies guys. I will be doing what said in the afternoon. I believe the sensors are working ok because they were replaced. Bob did a very good job in fixing the ECU etc. Yes the o-ring could be slipping and I will do a bit of CA as you said to hold it in place for the time being.
I will do the tests as you asked in the afternoon and will revert back to the list.
For now thank you all especially Bob for coming back to my rescue!

If the matter persists I will have no option but send it to Carlos. For the time being I wish to see what I can do before I decide. Again thanks to everyone

Reuben