Recently I've been hearing a faint fluttering noise coming from the front left area of my car. The noise flutters more quickly with increased vehicle speed, and intensifies when I decelerate in gear. It sounds like it is coming from the front left wheel well, but the sound could be coming through the firewall as well. I'd automatically assume it had something to do with the wheel, except for the fact that the noise goes away when I disengage the gear. Even if I keep engine speed constant, the noise stops when I depress the clutch.
I noticed the front undercarriage protection flap/cover lost a fastener clip, and may be causing the problem. However, that doesn't explain why the noise stops when I stop applying torque to a gear.
I also lost a small piece of foam on the driver side firewall/grommet area when installing my boost line, and since then I hear more engine noise than I should.
Also, a mechanic said I need new front tires, pads, and rotors if that means anything. Temperatures have been in the 60s-70s, although this car has seen some tough Winter abuse here in Boston.
2k2 USDM WRX: catless/bungless up-pipe, k+n air filter, b+m short shifter, ngk plugs, sti floormats, autometer mechanical boost gauge, ECUexplorer data logging, Continental all-season tires