Hooting sound coming from the intake

[jetco]

I have a 2001 4 cylinder 5 speed manual trans Camry that I recently purchased.
It has an issue I've never seen (or should I say "heard") before.

While listening to the engine run at idle, I noticed a soft but very obvious horn-like noise coming from the air box.
The noise was even louder with the intake hose removed and while listening at the throttle body itself.

I removed the throttle body and thoroughly cleaned it. This made no difference in the hooting sound.

Other issues I have noticed:
It is greatly sensitive to on/off of the throttle - almost like you'd expect a sticky throttle cable to act (which isn't the issue). In other words, you have to be VERY gentle to smoothly go from acceleration to deceleration.
The gas mileage is excellent on the highway (around 36), but rather poor around town (around 20).
Occasionally, I think I smell a little whiff of fuel if I stumble with the clutch and the RPM's drop to below a normal idle speed.

I am no stranger to Camry's (having owned maybe 10 gen1 to gen3 four cylinder models), and I drive quite conservatively.

I am thinking intake manifold gasket leak, but I don't think this is a common issue with 4 cylinder Camry's. Has anyone here ever encountered a hooting intake before?

So far, I am stumped!

[PhatRoyale]

Any videos of the sound you're referring to?

[jetco]

Originally Posted by PhatRoyale

Any videos of the sound you're referring to?

No, I don't have any way do to so.

I was just hoping someone might recognize the symptoms!

As I said, I am not stranger to older 4 cyl Camry's, and I've never heard anything like this before.