Strange noise, stalling

[wynng@tdn.com (Greg Wynn)]

Hello list, Today on my way to emissions testing of all days the Scirocco
spurred up a new problem.  Until today I've not noticed anything strange.
While sitting in line for emissions testing there was a humming sound coming
from what sounded like right under the middle of the car.  Was still running
fine at this point but just when I was getting close to the front of the
line the noise got a little louder and the car stalled.  It didn't start
right back up but after sitting for a few (30) seconds it started back up
and ran.  Promptly died again if let idle, still humming.  I wasn't able to
complete my testing because just as I pulled onto the testing spot it died
and I had to be pushed out.  After sitting for about a minute it started and
I drove the thing home with only one instance of stalling.  After letting it
sit for about 15 minutes it drove home (20 minutes) fine without any
problems or humming.  Any idea what this could be or at least some
suggestions to start poking and proding to find the problem?  Thanks.  Also
I am located in the Vancouver, WA area if anyone is able to offer some hands
on advice.

greg

'87 16v Scirocco