Well, just took my first trip in the Z last weekend and everything was going smoothly until I hit the highway. As I approach 85 mph a noise began occuring all the way up to 90 mph. Now I am still unsure of what the noise is, but it happens at no other point....just 85-90 mph it happens and it occurs both when I let go of the gas and apply the gas. Now I still have not gotten worried because it only occurs at that speed range, but has anyone else heard it? Its not soft and not too loud, and it sounds like the noise the car makes when it decelerates (the closest thing too it).....should I be really concerned???

 

its your rear and yes it's normal