After replacing a blown turbo intake gasket on my Nissan SR20VE (with turbo), my engine started Idling high (approximately 2000 RPM, and hunting/cycling between 1500-2000 rpms after warm-up. My turbo intake gasket was blown so I went through the laborious process of taking out the whole turbo manifold assembly and replacing all gaskets. I also changed the exhaust gaskets on the manifold and on the down pipe. I checked (disconnected) the MAF and the O2 sensor connections one at a time and no changes. I disconnected the battery to reset the ECU between each of the above tests. This problem started only after replacing the turbo gaskets. What's wrong?

The problem is resolved, after trial and error I narrowed it down to my IACV adjustment.