Just as too manybenz'z said test it out it may need some repair.. BUt if you have not already found through search, look for the brown vac line coming from your cabnext to the brake master cylinder.. It should go to the shut off valve, to the right of the fuel pump..

My line was just hanging there, I plugged it back in and presto it's all good again.

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Thank you for all the help guys!

"Old Gretchen" <--1983 300SD w126 cali. emissions (so it says on wdw sticker)
LIght metallic blue with dark blue interior. Odo stuck at 160,500 mi.

www.handydo.joolo.com