Welcome to the forum. You might try posting your question in the Sebring area.
The engines were changed somewhere around 2004, and the computers and sensors are different before and after the change. If you got a newer engine it won't work with the older computer.
If you can go back to the junkyard and compare the computer in the donor vehicle to yours, you should be able to tell by looking at it if it's the same.
If it's the same then you will have to double-check all your work to see what you may have missed.