Does it whistle when you rev it in neutral? If so try this remove the drive belt one at a time & then rev it up. Most likey its the idler puller for the ac.I have the same problem with my 2001 crv (250,000 miles)
I started the car after it sat for few months and that's the first time I heard the noise.
Drove the car for a few days and then the engine started running rough and check engine light came on (cyl 1 and cyl 2 misfires = consistent with vacuum leak).
- the whistling sure sounds like a vacuum leak
- I've looked and looked and looked and can't find one though.
After a couple hours of looking for a vacuum leak I decided to change seals on fuel injectors - but local parts stores did not carry - so I put everything back together.
Ran better after that and check engine light not on any more.
It still whistles a little (like a turbo) at 2000-3000 rpm.
Everything on here points towards the muffler though... which doesn't make sense.
Maybe a mouse made a nest in my muffler..... (explains why problem showed up after the car sat for 3 months)...
Has anyone ever found the turbo whistle sound coming from a vacuum leak??
Sounds like all posts were muffler issues.