Mine also did that when I first installed it per the directions. All you have to do is move the middle rubber bumpon all the way foward (toward hood edge) until it touches the deflector. Once I did that all vibration went away.
Yesterday I installed the Canadian deflector on my 05 and low and behold the damn thing was vibrating from about 65mph on, just like all of the posts that I had read on the subject. I installed it per the instructions. If you install per the instructions like I did the middle large bump-on does...
I just installed the same deflector on mine last night and guess what, I had the same vibration and buzzing from 65 on. I think I solved it today. I moved the large bumpon in the center further foward until it actualy touches the the deflector at all times just like the others. On my test drive...
On the news Sunday morning they were showing clips from the Bangkok Thiland World strong man comp and the guys were pulling trucks that were tied together. The trucks were not tacos they were full size and they did not look like our current Tundras. They were toyotas and toyota is sponsering it...