I experienced a similar noise this week while renting an H3 from Budget at the Denver Airport.
Scared the crap out of me, as it would manifest after driving for about 20+ minutes at highway speed. It comes on as the throttle position is increased.
Sounds like the "Flubber" car.....REAL hard to describe.
The weirdest thing about it is it goes away if you stop and idle for a couple of minutes.....
Me thinks.....a potential drive train issue...
3
Although no loss of power......just a real lame ass noise!