[Healeys] Non Healey/MG question

[Ron Fine]

I have a 2003 Honda Minivan with a front end issue.  Any idea as to what might
be causing it would be greatly appreciated:

I get a vibration or shimmy (left/right) through the steering wheel starting
about 65 mph.  Below that speed I feel nothing unusual.  The vibration is more
pronounced as I apply brakes and goes away as the car slows below 45 to 55
mph.  Tires are relatively new and I have rotated them (front to back) which
has no effect on the vibration.  Brakes are good (recently checked by dealer).
The vibration seems to be stronger on ruff road surfaces, almost disappearing
if I hit a very smooth patch of concrete on the freeway.  Shocks seem OK.  Car
is not bouncing up and down as it would with worn shocks.  There is no
vibration at slower speeds or when applying brakes at slower speeds.

I'm not really setup to work on the vehicle myself so I need to take it to a
dealer but I hate to go in without any idea as to what might be wrong.

Thanks for any ideas.

Ron Fine
61BN7
66 MGB