Anybody know what this black vacuum line should go to?

 

It looks like it broke off the closest vac sensor. The hose appears to have the plastic tip still stuck inside. Look over the sensors for a small hole near where the other hoses are attached. You may need to replace the sensor. Left unattended expect a check engine light to come on.

 

I can't find where it plugs into for the life of me

 

I did find this thread, it says the line is a vent https://www.f150forum.com/f6/i-think...ose-go-201950/

 

CHECK the line for vacuum. No vacuum? could be a vent. Since some vents oe vacuums are progressive so you may not be able to tell what it is unless the RPMs are up around 2500.

 

It's a vent

 

Well after battling with this thing all weekend changing o rings, I broke down and bought a used eatc off eBay and its working like a champ now!!!!