3000GT/Stealth :: Vibration And Noise On Car When Braking

Yesterday when I was on my way to a funeral, I noticed that whenever I braked kind of hard there would be a lot of noise and vibration on my car. The noise seemed to be coming from the front passenger side of the car and seemed to pull to the right a bit. I pulled over and took a look and everything looked fine but the sound and vibration was still there.

I drove about 10-15 minutes tops like this, parked the car, did the funeral home service, and 2 hours later while driving to the burial site (about 20 minute drive on the streets and freeway), everything felt fine. No vibration, no noise, nothing.

After the burial site I drove another 15 minutes to my parents house but this time you could hear the sound faintly and only when I braked hard. I jacked up the car and took off all the tires to take a look at the brakes/rotors and everything looked ok. I had plenty of pad left and the rotors seemed fine. With the tires on, I am able to spin the tires with my hands no problem.

This morning I drove to work and had no issues at all. No sound, no vibration, nothing. So at this point, I am stumped at what could have caused the noise and vibration earlier yesterday morning.