Well i don't bloody believe it, I think I have found the issue.
In diagnostics mode I kept getting error code 21, which is ECT out of range. So tonight I disconnected the ECT plug, and bridged the pins in the plug with a jump wire, and the car fired up and ran straight away, and ran smooth. throttle was plenty responsive, etc. It obviously ran extremely rich still because the ECU had no idea what temp the engine was at.
I have ordered a new ECT sensor which ill have tomorrow morning and hopefully have the car running good tomorrow.
This sensor failing over time, might be the reason I have never really gotten the ISC valve working with the EL computer on my conversion. It may also explain why more recently ive had an issue with the EL computer making the engine run super rich, have no power and not being able to idle, when it had been running for about 20-30 minutes. possibly because the failing sensor would start giving a false reading at a certain temperature making the EL ECU freak out. then once it was passed that temp range, come good again...
Are EL and XF ECT sensors different? as in different resistance, therefore the computers looking for different resistance to make an accurate reading? Maybe the EL ECU is what killed my sensor if it is in fact looking for a different resistance?
I will post here if the car is running properly again with the new sensor tomorrow.