I've had a strange whistle noise developing over the past few weeks coming from somewhere i the general vicinity of the throttle linkage/intake manifold (I know that is a big area)... It happens when I release the throttle and at idle, although it is sporadic and random.

Other info that may be useful is that I have had a particularly rough idle for some time (Recent EAT chip improved it a little though), and it doesn't seem to have the same performance as it did when I got it (EAT chip has also improved this!).

After a lot of reading around it seems to suggest a vaccum leak - Pgrindstaff has been kind enough to reply to a PM I sent him as in one of his threads he describes symptoms exactly like mine.

I was hoping someone with m30 knowledge may be able to direct me to the vaccum hoses to check, or how I can differentiate these from other hoses at least so I can go find them and make sure there's no cracks etc, before looking at the intake manifold gasket. If there's anything else please suggest, and what methods I can use to check things as I'm fairly new to this vacuum business...

Pgrindstaff has suggested this small hose could be the issue and I am sure I have read this commonly causes a problem on the m30...
http://www.bimmernut.com/forum/showt...ht=vacuum+hose

Oh and can I ask is this problem an urgent one to sort out? I'm assuming its ok to drive as long as there's no running problems - I just don't want to cause any damage by driving it with a vacuum leak...

TIA...