I recently put together a B18C with a B16 head and B16 tranny. I am running a GT3076R turbo with a Full Race header and Full Race downpipe. I got it tuned about a month ago and during the tune the car was idling to about 2k and go down to 1k. It constantly goes up and down and eventually settle down to 1k after letting it sit for a while. What can be causing this. Any input would help since I am new to the turbo scene.