Car has been 1JZGTE swapped since october, just converted it from auto to CD009 6 speed finishing yesterday. Everything works fine(tested on jackstands for clutch engagement etc) except when i blipped the throttle in neutral it would rev up from the 900rpm idle up to ~2500rpm then fall back to 1700rpm. Once it falls to 1700rpm it stays there and will not idle down until turning the car off and turning it back on. Without fail it idles perfectly until it gets any gas at which point it gets stuck at 1700rpm.

The car never had this issue previously but it has sit over winter and a good bit of the summer while I did the swap as funds allowed. Ideas?