First I would check with your tires, I have had this problem and one of my tires was bad. If not,get an alignment, they can check the tires there too, you might of hit a pot hole or a bump too hard and the all mighty f-bodies, adjust very easily to bumps. I also have experienced shaking brakage. The stock rotors suck on these and I have had to get these replaced and break them in correctly. These are my opinions, anything could be wrong. Let me know what it is. Thanks.