So I've recently puchased a '94 Jimmy, and as expected for a $1000 truck its got a few issues to be sorted out. I've figured out my power window problem, but the truck also has a couple other issues. It has a bit of a rough idle, which isn't too bad, but I know its not right. I cleaned the EGR valve and put a screened gasket on it, but not very much changed. After doing an oil change, I was getting a closer look at things under the hood, and some of the vacuum lines look to be dry rotted. I pulled the one off at the cruse control diaphragm and blew into it, and noticed there was no resistance. After examining, there is a vacuum "T" at the back of the motor, with one part of the T looking broken off. Another part of the T wasn't even plugged into the intake. I ended up plugging it, but I still have a rough idle. Then I hooked the one part up to the intake manifold. Heres what my symptoms are:
Rough Idle
Vents stuck in Defrost and floor no matter what position the heater control is in
Cruise control wasn't working, but I got it to work
4x4 doesn't work (electronic transfer case)

Since all these systems use vacuum, I was hoping to replace all the lines, and make sure everything gets hooked up properly. Does anyone have any suggestions, or maybe even vacuum diagrams? I was thinking of picking up a haynes manual, but I've got a couple of those for other vehicles and they seem to mostly have general information.

 

These should cover things well enough:

 

wow, thats exactly what I need, thank you

 

So I'd like to give a little follow-up on what i've done so far and what is working now for future reference. My cruise control is working 100% after hooking up all the lines and changing the cracked old lines. Today I found the line that provides vacuum for the vent controls was unhooked, so I hooked that to a source of vacuum and now my vents are working properly. As far as my 4x4, I have traced the lines to the battery, where there is one line with a bolt in the end of it acting as a plug. I haven't looked under the battery yet to see where it should be hooked in, but I'm betting that is the source of my problem. Thanks for the help, I'll post again when I fix my 4x4

I'd also like to add that my rough idle was actually a result of a leaking fuel line inside the intake manifold...the ones that lead to the spider injection unit. The pressure line had rubbed a hole in itself and was leaking inside the intake, and the pressure regulator was leaking also. I replaced both of those and it runs a lot better now.

 

Well, I fixed my 4x4 also. It was a vacuum related problem, with the line being cracked. Now it works great

 

Thanks for the follow up. Glad you got it fixed!