What is this? It has a line that goes to the intake manifold that, I'm assuming, has been disconnected since I've had it. Only driven about 10 miles. When I go to plug it back in to the manifold the jeep only runs for about 10 seconds while it dies!

This is a 2001 XJ Sport 4x4 4.0. Thanks for any help and apologies if this is a dumb question

 

its a vacuum valve of some sort. (just pointing out the obvious) but since it is electronically controlled...it almost looks like cruise control, but im not too sure from the pic. does it only have the one hose and one harness on the front? or is there more to it?

if its just waht the eye can see, then it could be a vacuum sensor that controls the manifold pressure. and if it is bad then once it gets a reading it tries to control the vacuum, thus killing the engine.

 

That canister above my hand is connected to it via hose...just traced another hose that connects from he bottom of it to the drivers side of the hood and then runs under the drivers side all the way to the back next to the gas tank. It's dry rotted pretty bad in a couple spots.. Some kind of vapor line? But why would it die when I plug it back into the maniflold if it's suppose to be drawing in?

 

That's a Leak Detection Pump.

The emission decal on the firewall should show the EVAP vacuum line routing.

 

is the spot on the manifold capped off inplace of that hose?

 

Nope..looks like it was dry rotted enough to fall out..when you try to slip it back on it's just barely on..like I said though, I tried to put it back on and start it but it just dies. I take it off and it starts up and stays running....?