I tried taking off this hose, and the plastic nub that it was connected to broke off.

What the hell is this thing?
It looks like a vaccum hose; but I don't feel any pressure.
Does it do anything?

Some reason the hose is vinyl, should I change it to a rubber hose?

 

its for the evap. just leave it alone

 

it broke off ....don't fix it??

 

It's for smog reasons. Next smog check if the guy is more thorough than most you won't pass the visual.