What is function of black plastic tubes connected to idle air control valve on 560?

Black tubes about an inch in diameter on inside of each valve cover. They don't seem to connect to anything.

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They are connected to manifold vacuum.
#266 is attached to 262 here: http://www.detali.ru/cat/oem_mb2.asp?TP=1&F 7048&M7%2E967&GAr2%2E313&Lv5%2E707&CT=M&catM&SID&SGR0&SGN

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Ooops 242, not 262.

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