i am piecing together a 2000 civic and it has a y8 motor in it and at idle it surger from a grand to two grand and throws a code for iac so i found the plug that goes to the iac but where the iac goes it is blocked off so im wondering if it is the wrong intake manifold or what...any help would be awesome

 

From my beleifs there is a difference between standard and auto intake manifolds. You might want to look into that. But then agian I can be wrong.

 

i have a automatic ecu and automatic engine harness, a automatic has to have some sort of iac valve

 

The IACV on an automatic is on the throttle body I believe its been too long since ive seen one here on island. Here see check this site and it wouldnt hurt to google it down theres alot of issues about this. Check this one might help a little to give you an idea https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/d16y8-intake-manifold-2363371/