Hi, to start, my car is a 2004 Impreza 2.5TS 5MT with a 2000 Impreza L phase 2 EJ22 in it.

To complete this swap, I transfered the intake and exhaust manifolds with any sensors and such associated, as well as the cam and crank sprockets. While the EJ222 was out, I replaced the valve cover gaskets and timing belt.

I had a hiccup when getting it started that I didn't swap the cam and crank gears, so I had to go back in to do that, and when I fired it up, it would not go lower than 4000rpm, sometimes up to 5000 and I shut it off before I can see if it will go any higher. I tried cleaning the IACV which didn't help, followed by replacing it, which brought my rpm down to about 3000, before climbing right back up to 4500 a couple seconds later.

I am getting codes P0519 AND P0113 currently, although the airbox and thus, IAT sensor, are not currently attached.

 

Anyone have recommendations on what would be causing this ridiculously high idle?

Thanks. 

Make sure the throttle plate is all the way closed.  I'd get the airbox and all hoses back on/connected.