Yup, my car is turning into Eeyore.
I'm pretty sure that it's a vacuum issue. I'm posting here for some input before I open up the engine compartment and try to trace it down. Here are the symptoms...
- The sound is coming from the right vent (behind the passenger door)
- In general the engine runs great.
- It only moans when the engine is pulling a vacuum. i.e. ...
- - When the engine is warm and idleing.*
- - It goes away (temporarily) when I tap the throttle
- - I can hear it briefly when coasting, but only when I initially start to feed in some throttle
- It's been going on for a while, but gotten significantly louder in the last month
* Most of these seem to be determined by when the e-throttle is closed, which is generally not the case on over-run or when I'm coasting.
When I get an hour or two, I'll open up the engine see if I can ID specifically where the sound is coming from. But any thoughts on suspects before I get in there will be helpful.

- John