@steve429 I did this switch to my car over a year ago ,and still drive it till today the engine runs fine an has no issues , besides the check engine light comes on for the iac once in awhile but does not effect how the engine is ruining . I really don't care that my engine light comes on for the problem because it does go off but when it's time to get a sticker I reset the light by pulling the fuse but always check to make sure there are no other problems occurring when the light is on just incase . And that hose is still off and when the light is off there isn't much suction coming from that hose but when the check engine light is on there is a lot of suction coming from it . I'm pretty sure that is caused when the IAC is opening and closing , as for that working or not I've seen in some case's it can get stuck so you may have to spray some cleaning in that port on the intake. And for the throttle body I did switch it so the IAC would match up . But I did not change the whole head I left that alone and left the hose off . Hope that helps

 

Since your post is 12 years old, I assume you have solved your problem. I think I have the same issue, P0505 in 1999 Camry after switching engines. Engine ran great except for fast idle and check engine light. I also cannot pass smog test unless check engine light is on when ignition is on and off when engine is running. I am going to switch the throttle body tomorrow, but I cannot figure out where to attach the third vacuum hose from the throttle body since there is no port in the head on the new engine. You cannot just leave the vacuum line open, as it will cause vacuum leak. Did you try just plugging the third vacuum port on the throttle body? I read that someone with the same problem was told to use a T-adapter, but he did not say where to connect the T.