My LX450 will get a vibration from about 30-65mph and it's always random. It's like a really bad balanced tire with a roar. It doesn't increase as the speed goes up or down and doesn't seem to be a wheel bearing. It may stay for 10-15 minutes then it just goes away and drives smooth as silk? Doesn't it in neutral or drive so it shouldn't be in the drive line. I'm thinking bad tire or balance. Seems weird it comes and goes like that. Any thoughts? Thanks!