Yea.

 

Subdivisions, check the front brake backing plates. They may be hitting on the rotor. Ive seen this issue at the dealership I work for and it was an issue with my car as well. We are not sure what causes the backing plate to shift, but all you need to do is reposition it away from the rotor. Hope this helps.

 

No after market exhaust.
It sounds like its coming from the front drivers side wheel or from the front end, so the brake backing sound logical.

 

Back to the original post... "Normal"
Before I traded for my 06, my 04 AT was getting 9-12 MPG.
My 04 was in the shop a multitude of times... after flashes, part changes, fluid changes,
phone calls to Tech Support and who knows what else...?!?
I was told "my poor mpg was Normal for an AT"... and I must be driving the car
incorrectly or racing it... Yea. Right! Racing an AT!!!

Flash forward to the new owner. He called me saying,
"You were getting bad gas mileage weren't you." I answered "yes".
He told me that the MAF was filthy and that the 04 had the incorrect plugs with
an incorrect gap...
He cleaned the MAF, replaced and properly gapped the plugs.
Now he's getting 17 MPG with 100% stop and go driving...

So don't buy into the "It's Normal" BS. When something is wrong, it's wrong.
The problem is finding someone who is more then just a part changer to diagnose the problem(s).
Someone to take the initiative and go beyond whats in a repair manual.
Good luck!