I've noticed that some of the vacuum lines on my 307 aren't routed according to how they appear on the vacuum diagram under my hood. I'm not sure if it's just me but I find that thing incredibly hard to follow. I'm not 100% sure what all the components are and what role they play in my engine running properly. There are some vacuum connections that aren't even represented on that diagram or some that appear to be different. For example the "VAC TANK" mentioned in the passenger front corner of the engine compartment only has one connection going to it, not two like the image shows. I could use some help in properly routing everything so I can take some of the guess work out of any current or future engine issues. For reference my car is a 1989 Cadillac with cruise control and the Y version of the engine.

 

Perhaps this might help you
https://classicoldsmobile.com/forums...ns-videos.html