This is my 89 IROC TPI and I was pulling the fuel rails to replace the injectors when I noticed this empty vacuum socket (yes, I just made up that term, not sure what it’s actually called). It looks like a hose should be attached but I can’t find any loose hoses lying around. It’s a sort of junction where two smaller hoses can attach to a larger one, and there is a small hose in one side but this one is empty. The whole reason I’m swapping my injectors aside from them being 34 years old is it idles like crap and stalls often. But now I’m thinking maybe this has something to do with the issues, or is it completely irrelevant? It’s located below and to the passenger side of the distributor.

 

The vacuum line starts under the throttle body. Goes to the egr solenoid. From the solenoid to the egr valve .