I just rolled over 3000 miles on my 05 King Ranch 4x4 SuperCrew yesterday. I did my first real interstate trip and noticed a vibration in the steering wheel between 73-77 mph. It is not a bad vibe but it's enough to aggravate you. I can feel it through the seat, steering wheel and floorboard. It's hard to tell what it is, feels like a bent wheel but it only vibes at those speeds, so it can't be a bent wheel.

I did read some of the vibe threads but it looks like there is no single cause for this problem.

Mine is 3.73 LS with off road 18inch BFG's.

I hope it doesn't get worse.

 

I also hope so for you...but go down and make sure get the tires balanced and alignment checked before causing yourself much worry.

 

Mine does the same thing, 2005 SCab, also, at 30-40 I feel every bump in the road, not real happy with it. It goes back in today.