PCV valve location

Hi, my cat listed above (with throttle body injection) is idling very rough, shutting off at stop signs, that sort of thing. When the engine is cold, it actually runs great, but once it warms up the idle is terrible, it drives terribly under 40 mph, and great over 40 mph. Has plenty of power.

Anyway, it seems like it could be a bad PCV valve. The only problem: I can't find the PCV valve! Can anyone tell me where it's located? And better yet send a pic or diagram showing where it is.

Thanks!