My 2011 GS350 makes a 'hoot' sound at certain speeds and throttle openings. It's particularly noticeable at 55-70mph and very slight throttle opening. Press the gas a bit further and the sound immediately stops. Let off the gas, same result. The sound is constant, so it might more accurately be called a 'whooooo' sound. And the tone goes up and down with speed.

I don't notice it at all at lower speeds. It's possible that the tone is too low for me to hear. I also don't notice it above 70mph though, and the tone would definitely not be too high if it were still there.

I thought it might be that weird plastic box hanging off the intake tube, but I removed it and still hear the sound.

Any ideas?

 

For starters, check your air intake system to make sure your intake scoop, air box, intake tube, PCV hose, and resonator are all connected securely and there aren't any holes or cracks in the parts

Also, check the body panels and seals to be sure that they're all intact and where they should be

 

Sorry couldn't resist...

 

Good point, could be that Bubb Rubb somehow got stuck in OP's airbox

 

LOL at the video.

I had the engine cover off and examined the intake stuff. It's all good. No Bubb Rubbs in there.

I can see how a body panel might make the sound but I don't see how that would vary with throttle opening.

Any other ideas? I'd be surprised if I'm the only one with this sound. So far every other noise I've chased down on the car has been figured out by somebody, somewhere, before me.

 

Hmm well if it's not from the intake, you may have an exhaust leak

EDIT: If you live in a county/state that puts a lot of salt on the roads/freeways in the winter, you may well be hearing a pinhole leak. I've seen this problem discussed here before, usually by people from your neck of the woods or Canada. There's a heat shield on the pipes between the primary and secondary cats – salt can get stuck in there and if it sits there for a while, it can rust right through the pipe.

 

Ooog, exhaust leak. It's possible I suppose. The car definitely saw winter weather before I bought it.

 

This would eliminate the transmission: While driving, carefully put the trans in neutural, let the car roll, does the sound stop? While coasting and in nuetural, mildly rev the engine, does the sound change with the revs not vehicle speed?

 

I had an exhaust leak because one of the gasket got pinched and broken in half. Check your exhaust gaskets

 

My car did the same. After replacing the alternator it stopped.

 

I believe there was a technical bulletin related to the carrier bearing assembly causing a whine noise when coasting. The fix was a simple installation of a washer.