Dear forum, in search of the reason for the undisturbed idleness of my 1994er Vectra A (C18NZ, to the best of my knowledge undisturbed or -getunted) as well as the m. E. too high consumption I went on the search for wrong air and looked at the vacuum system around the Multec times more closely. I noticed the following “connection” which I also cannot explain after reading the “Now I help myself”, the Haynes and many forum contributions here and elsewhere (see photo : The blue hose at the top left of the picture is, to my knowledge, the control line to the activated carbon tank of the tank ventilation, which, depending on the load condition, switches on and off the intake of the fuel vapours. This control line is connected to the Multec via the green marked hose. So far, so well, until here I understand everything (I think =). What I don’t understand is the red marked junction to the underpressure line of the brake power amplifier. r air sucked to the intake manifold of the 1st cylinder, which, in my understanding, results in this cylinder running thinner than the others. Consequently, the idle time becomes quieter and also slower when I press the red-marked hose, and again faster and more restless when I release again. Does anyone know if this is so original, and if so, why, and if no, how it has to be right? Thank you!