high idle jdm swap

just finished swap,kicked over instantly.
runs smoooooth, however idle wont come down from 1480rpms
no vac leaks that i could find
no sticky linkage
anyone got any ideas?

 

Grab the throttle body and physically turn in towards closed. Grab from the spring loaded part on front of it hooked straight to butterfly valve. Report back if that changed anything

 

Do it while the engines running

 

no effect

 

I would clean your maf sensor, and idle air control valve. Did you use the idle air valve from the jdm engine or your old one? It's on the bottom of the throttle body, the thing that the coolant lines hook into

 

swap the IAC/ manifold from your old motor, if you have done this already let us know.

 

tbs might be the issue

 

Are the IAC's model year / ecu dependent? I'm swapping a 99 engine into my 98 and plan on using the same IAC, but wanted to keep the other one as a backup.

 

The other one will work as a backup