Iwas talking to a friend of mine and he saw that there was a hole on my lim that didn't have a block off plate and him and i couldn't find what it went so i thought i would ask here and see what it was for.

 

its for the split air pipe, if you've capped the acv off, its been blocked off from the other side

 

check valve. it's a pipe that attaches to that spot and runs by your downpipe and connects to the catalytic convertor with a hose.