'91 Astro...vacuum problems?

[pearldrum944]

There are three things wrong with my mom's '91 astro:
1.Idles bad, but is fine when given any gas.
2.Dash vents don't work, defrosters and floor vents do however
3.Cruise control went out.
All three of these seemed to happen one after another over a period of a month or two. The best I can figure is that the problem is a vacuum leak. Does anyone have a vacuum line diagram for a '91 model? Also, Are there any tips as to where the leak could be? Thanks.

[88bronk]

No diagram. but I had the same problem. The plastic vacuum line was melted near the distributor on the right side ( when you are sitting in the van). Just trace the vacuum lines very carefully, they are plastic and get brittle because it gets very hot under the cowl. I used rubber hose to replace the complete section and tried to cover every line I could reach with aluminum foil ( some insulation is better that nothing). I went for the ventillation problem first and removed the heat/AC control panel. It is very fragile and hard to reinsert, I broke it and had to replace. I had to use a dremmel tool and cut out some of the plastic molding inside the dash to get the 2nd control panel back in. I consider my problem was a major vacuum leak because a line was broke and not just a small crack in the line that can be found by spaying WD-40 or small enough to cause a whistle. If you find any other lines that look damaged you should replace them too. Good luck. igw