My car has a shimmy/shake that is very noticeable above 50 MPH, and of course gets worse at higher speeds. The thing about this is that is comes and goes. The shake is in the steering wheel, floor, dash, and seats. (pretty much everywhere). As I said it comes and goes in waves.
I've recently replaced brake rotors and ball joints. There was no play when I looked at the tie-rod ends, but not ruling them out.
My tires are old and are starting to cup, and could be out of round but haven't checked. Could crappy tires cause vibration that comes and goes in waves or is it something else?
Thanks for the help