big mess!!

alright the other day i was driving my car and made a pull around a car to pass him, after that i relized that when my car would go down to idle the engine would rev up to 3 grand and go back down to 800 and go back and forth
first thing i thought was that it had to be a vacume line
checked every single on and cant find any one lose
any other ideas?

the bobbing idle is in perfect rhythm

this really is a vacuum leak !