I'm looking for some help on the vacuum line routing. First, are all of these lines emissions related? The only schematics I can find of any sort of vac line is in an emissions diagram. I've got an '89 IROC 5.7 that I just got about a month ago, and I've found all kinds of screwy stuff with the thing. Anyway... I'll get to the point. There's a vacuum line that begins on the driver's side at a diphragm next to the charcoal canister. It tees off a short distance back, and I believe it's supposed to go to a vacuum tank. Further back at the firewall, it tees again. On my car it tees on the drivers side close to the plenum. Well I found the line that comes off was just laid beneath the plenum between the runners. I can't find any type of vacuum port anywhere! Where the hell does this thing go???

 

Try doing a search. I think Vader posted a diagram not too long ago.

 

That line is for cruise control I believe. I think it goes somewhere under the plenum, but I'm not sure. I can check my old TPI intake tomorrow for if I don't forget.