Remove the "tape" and cap off the vacuum port you are no longer using properly. You can buy vacuum caps from any auto parts store for cheap.
Were you using the B16 TB on your stock Y8 IM, or is it a new install along with the Skunk2 IM?
I have all the caps now an i blocked them all off. an i have new IM an TB gasket. but i got a Y8 TB gasket should i of gotten the B16 one??im had the same problem.
i never was able to cure mine. the only thing i could thing of too is the throttle body gasket. if you reused yours that could be the issue and same with the intake manifold.
but once you get it figured out let me know.
mine used to be that way..now after my motor swap mine revs from 3500 to 1000 and bounces back and forth.
definetly get those caps from autzone. you can get an assorted pack for around 4 dollars. thats what i did.