v6 3.0 vacuum question

I was browsing some threads and came across one asking about a possible vacuum line missing.

turns out nothing is attached to it but it is capped off. mine isnt capped off and I am wondering if it should be?

I know its dumb but I am new to the 3.0

here is a pic

 

I don't see any vacuum lines that aren't connected or capped off in your pic.

 

Stick your finger over it when the engine is running, if there is vacuum there it should be capped. If it's sucking air you have air bypassing the VAF meter and the engine is running leaner than it should be.

 

I should of thought about this in the first place.

thanks.