All those symptoms taken together suggest a worn lower control arm bushing allowing the alignment to change. That would make an intermittent pull to one side when braking or accelerating. A similar symptom can occur from a tire pull which can also cause a vibration. Don't overlook something as simple as a warped brake rotor.
GM also has had a huge problem with abs wheel speed sensors that are built into the front wheel bearings. The bearings develop a little play, which is normal, but it's enough to cause dropouts in the speed signals and make the computer think that wheel stopped rotating. You will feel that as a buzzing in the brake pedal, and possibly the entire car, but only when braking, not when just cruising.
Wednesday, July 27th, 2011 AT 10:54 PM