I got a brand new 2011 Mazda 3 i Sport 4 door sedan in May and it’s been great so far. Lately though, I have started to hear a sound coming from the back left hand side of the car. It really closely resembles the sound of tapping one’s finger on a countertop. When I’m stopped, there’s no noise but when I go I can hear it. As I go faster it goes faster as well and when I slow down it slows down. Does anyone have any idea at all what is going on? Thanks 
Mr. Obvious, Here. Have You Checked The Tire At That Location To See If There’s A Stone Or Something Stuck In The Tread ?
CSA
maybe not the tread but the brake dust shield. Wiggle the shield a little bit then drive it around a parking lot to see if that clears it up