The drivetrain of my 92 accord lx (170k miles) vibrates slightly when cruising at highway speeds, but it gets much much worse when trying to accelerate at these speeds (when the engine is working hard). I've recently put new rotors and new tires on, got the tires balanced again and got 4 wheel alignment done yesterday... Both outer tie rod ends were replaced 2 weeks ago. Both cv joints have been replaced in the last 2 years. What is it? Could one of the cv joints be out of balance?