RX-8 Vacuum leak!
 

Hey guys i just got back from work and i decided to go and admire my engine so more, then i noticed a vacuum like sound coming from the engine. I had one of my coworkers take a look at it and he said its a vacuum leak. I didn't address the problem today because it was too dark to do anything so i'm going to do it tomorrow, but before i do, do you guys have any possible reasons or suggestions?

check the one way valve behind your UIM near your oil filter. Perhaps you inadvertently popped the line while changing your oil filter...

ok ill check that

Check engine light on?

Nope its not on.