Hello; my 1992 400e has been idling rough and when looking over my vacuum lines I found a really small transparent tube coming from the back of the valley plate between the cylinder heads and ending around the throttle body. As it was not plugged into anything, I looked around under the intake but couldn't find any fittings onto which it could attach. Does anyone know where that tube is supposed to go and what fittings, if any, I will need to get it there? Thanks for any suggestions. twbolander