does it go away at higher speeds and come back after hard braking? If it does your caliper is stuck, the higher speed is burning the pads down to the point of not contacting the rotor anymore and then when you force the caliper back after braking the pad is rubbing again.

try putting the car in the air and pushing the break pedal as hard as you can for a few moments, put the trans in neutral and leave the ebrake off. spin each wheel by hand and find out which one grabs at specific intervals or doesn't spin as easily as the rest.

Wala! you've found the stuck caliper. The problem could be either a stuck slide (easier and less expensive to fix) or a stuck piston (get a new caliper and flush the shit out of your system)
If it's a stuck slide just get a new slide bolt kit and run some fine emory cloth through the hole and make sure to lube the piss out of the slide bolt. relace/machine your rotors and replace your pads (both sides, don't be captian half-ass)

if the piston in the caliper is stuck it's probably water in the system and you might want to consider rebuilding or replacing the other calipers.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!