Trying to track down a vacuum leak and noticed this...what does it do? It kinda looks like a hose that's come loose? 88 4Runner V6

 

Fuel line to the Cold Start Injector. If it's actually separated from the crimp (hard to tell from the picture), fuel should gush out of there as soon as the fuel pump comes on. Since that doesn't happen (I'm assuming), you might want to find the other end of that line.

 

Thanks. It doesn't leak any fuel that I can tell. What am I looking for on the other end of the line?

 

This photo is from my '94, but I think your '88 won't be that different. My CSI is just cut off on the left side of this photo., but you can see the entire flexible line. Since no fuel is coming out of your line, I'm guessing that someone somehow blocked the line (which is not trivial; it's a "high" pressure line). You're not going to be able to see the Rt fuel rail unless you remove the plenum.

 

Okay that is the cleanest engine bay I have ever seen. I am jealous! Is it a new engine? I wonder how or why someone would block that line? I want to take my plenum off to clean it up with a wire brush to make it look good again and while I am in there I will be able to see where that line goes. Thanks for the help!

 

Looks like a vibration damper (foam sheath) from here, like scope said if it was disconnected it would be shooting fuel out.

 

O.P. If you end up replacing vacuum hoses,pls note total length needed for each size and share.

This^^^
To protect line from abrasion.