Quote Originally Posted by 94Cobra View Post
I gave up and put 3 K&N breathers on it and eliminated the pcv entirely. The guys who run Big Shot Dyno said the pcv probably hurt my power some last Saturday. At WOT when the pcv cannot evacuate enough fumes, the overflow goes right back into the air inlet tract. This contaminates the intake charge, lowers the compression ratio and can cause detonation. That makes sense to me.
The oil actually lowers the effective octane of the fuel mixture, not compression.

You may need to check the tune if it's rich. Ask your tuner. The stock eec-iv calibration actually accounts for some airflow through the pcv system.