ummm...it burns as in it gets so hot that smoke comes out from under the wheels. Yeah, I know. Yes I do brake more often than normal, I'm a pizza driver. Hard braking alone doesn't explain these probs though. My car should at least stop normally for a small period of time before my hard driving begins to "overload" my "perfectly functional" brakes. That's not the case, my car's braking sucks instantly from the second I get in the car, everyday.

I don't think its glazed rotors or anything, because the rotors were just recently replaced along with the pads, and after i went SUPER SUPER easy for the next 100 miles, the braking problems persisted.

Did the 2nd brake booster test waabaah suggested, and the pedal did sink after turning on the car. Brake booster seems to be okay.

What is this proportioning valve? I've never heard of this part.