Sorry about that! I meant to add a post to an ongoing thread and hit "new topic" instead. I have a 1986 300E, and my car isn't the first 300E I've encountered having this occur. A lady I work with has a 1987 300E which had the same condition. New hoses fixed her problem as well. I only posted my solution because "porous hoses" were not the first thing that rang to mind for me. I was thinking fuel or gasket leak.