Honda civic won't idle

I have a 1998 honda civic ex and had a d16y8. That motor was replaced with a d16y7 out of a 2000 honda civic. It has full exhuast, skunk2 d16y8 intake and a 76mm throttle body also skunk2. I replaced the iacv and converted it from 3 wire to 2 wire. It starts perfect but won't idle. It idles at 300 and goes up and down and almost dies and will die sometimes. Just sitting in driveway with no electrical load. I also replaced the stock y8 ecu with a y7 but I still have y8. So why won't it idle? I have no idea.

Assuming you converted the wires in the harness properly, you wouldn't be able to swap the ecus and make it work. The y8 and y7 computers have different pin locations for the iacv. If you are using a y7 engine you have to use the y7 computer. But, depening on which harness you used, you need to move certain pin locations at the ecu terminals as well as at the iacv.

Check this out:
http://honda-tech.com/honda-civic-del-sol-1992-2000-1/00-civic-ek-iacv-3-2-wire-converion-2926743/

Take it to mechanic