Ok, before I start explaining I want you all to know that I've done plenty of research and although I have found similar issues none fit my description.

I just purchased an "as is" 05 TL Auto w/ 91,000 miles. The car has been kept in pristine condition inside and out and has all of the regular maintenance records to go with it.

On my way to work I had the windows down for the first time and noticed at a very specific part-throttle position that there was a faint but high-pitched squeal. It sounds identical to brake squeal. It's a steady sound that doesn't fluctuate with speed or rpm. As soon as I either push for more gas or release for less the sound goes away. I've tried replicating the sound in park and in drive while power braking. Nothing. Only while moving at that very specific throttle position does it start. I can only hear it if the drivers side window is open.

I can live with it, though. I'm just curious to know what it is and if I need to address it. I need the car to last about 8 months before I deploy and get rid of it. Thanks for any help!

 

Ive never heard of a problem like this.
Try checking your throttle body and make sure it is clean, and also the intake filter

 

Ok.. So the throttle body is clean and secure. It does have an aftermarket K&N intake and filter. Filter is new and all connections are secure. I've tried to replicate the sound in park and all I get is intake suction. Only in drive at a very specific throttle position it squeals. It's especially annoying because it starts to squeal at the point to maintain speed for city limits. The trans seems to shift smooth.

It's really beginning to piss me off considering I can't drive with the windows down or else I'll go nuts. I bought it used with a limited 3000m engine/trans warranty, but of course the stealership isn't going to acknowledge anything that'll cost them money if they can help it.

Has anyone here ever experienced a high-pitched squeal at all? It's either a very steady high-pitched whistle or squeal is how I would describe it. I love this car but I'm ready kick her in the face!

 

Cold air intakes have been known to create a whistle sound at certain throttle positions

 

With my SRT4 at 10psi WOT, I can somewhat compare that intake whine to what I'm hearing with my TL. But at just part-throttle keeping it steady at 40mph it doesn't make sense that it's the CAI. It sounds like brake squeal. I'm gonna try messing with the intake sometime this week to see if it is in fact the intake to cover my bases. Not being able to replicate it in neutral makes it impossible to find.

I have read quite a bit about trans issues and different sounds that makes. Could the trans cause a high-pitch squeal?