I'm having a really weird issue and hope you can chime in. So with the can installed I get this weird random rattle almost sounds like its coming from the dash and only hear it in the car. Checked under the hood and everything looked fine, I kept the can installed but removed the hoses and connected the stock PCV-Manifold line and the sound completely went away. Hooked the can back up, rattle is back.
Does yours make some weird noises? I'm wondering if the can is acting almost as a sound amplifier for noises in the crankcase at certain RPM]
edit: its not just me, https://www.civicx.com/forum/threads/mishimoto-catch-can-updates.5443/