Engine sawing…

Hello community, have a problem that makes itself felt like follow. Start and then the engine runs unround…between 500 and 1500 revolutions. then opened the bonnet and after a few minutes found a vacuum hose which lies freely in the engine room. He does where also the other vacuum hoses come from. Was also just in an ADAC workshop because I needed a stage after all I could not see where the one has to go. Even the mechanics have visited 20 minutes but everything without success. And since I am just in Jena and the Volvo workshop closes here already at 12 o’clock I can not expect any help there either. the end of the hose was put on it with a rubber sleeve which is torn in and at one side something is gone. So I thought that somewhere below the bridge is somewhere to settle. But I can’t find anything. Have all conceivable length paths checked where he might fit. …but I am with my Latin in this regard at the END. I guess there it sounds as if he is attracted to LUFT. But I don’t know how to do it with the LMM or maybe I’m grateful for the help.