Posting for my buddy. He did a AOD to T5 swap on his 89 LX, he got everything but the T5 harness and computer now he idles at like 1k rpms. If he swaps over just the t5 harness....would that fix his idle? Or does he need to swap the harness and the computer to fix it?
If you swap over the t-5 harness and computer, you'll need to change or re-pin the O2 harness as well.
It may very well be that he just needs to reset his idle single he no longer has the drag of the AOD stall converter to lower his idle.
Unplus the IAC and use a screwdriver to back the idle down with the idle set screw. Then reset the computer by unplugging it for 15 mins. Then hook the IAC back up and restart and let it learn the new idle strategy and see if that makes a difference