Strange noise on 2005 4Runner

[Mpac1]

Car has developed strange noise on startup.

It sounds almost like a loud fan noise (whirring sound in the MAF engine area). Doesn't vary with engine RPM, is constant sound. This is the V8 engine 2WD model.

It will make this noise for a minute or so, then stop.

Any ideas where to begin will be appreciated.

Thanks!!