A few weeks ago my '99 SL2 started making a disturbing noise. When I am braking to stop, I'm getting a noise that from what I can tell seems to be coming from the front driver's side wheel or tire. It is difficult for me to describe the sound in words: I'd like to say it's sort of a low-pitched clicking noise, but I could also say it's sort of a "whup whup" flapping (or rattling?) noise. (It really does sound like a click or rattle, except those words usually describe high-pitched noises, and this is fairly low-pitched.) The noise is definitely correlated with the spinning of the wheel - as the car slows down the noise slows down as well, and stops once the tires have stopped. No noticeable shuddering or vibration associated with it.
My car was just inspected this morning and passed without needing any work, so whatever the problem is, it wasn't something found during a VA state inspection. I tested the shocks and they behaved normally. My tires were rotated 3,000 miles ago and the wheels were balanced with the purchase of new tires 15,000 miles ago. Car drives straight as an arrow, so alignment doesn't seem to be an issue. I was inclined to think perhaps the tire was cupping anyway, but when I examined the tire it didn't look that way (I might have just not known what I was looking at?). My other thought was that it might be a worn brake rotor. How long might one expect brake rotors to hold up? I purchased the car at about 95,000 miles and it is now at 125,000. I am unaware of any maintenance done prior to 95,000 miles, but have not had any brake work done since buying the car.
Any ideas?