I agree with Jim and XI but also check lug nut holles on each rim, if some of them are oval looking from too much torque that can cause a lot of problems, beleve me I am thinking to put back my black stock steel wheels I think they just sit on the hub better and if you have a nice rims and they are not factory then probably you are dealing with some engeeniring issues that could be creating problems for you at certain speeds. This is just my opinion. Or maybe she is afraid to go faster than 80
