Everything Bill says, do.
I'm sure he and I are both assuming that you have new shock absorbers, new tires/wheels, and that all steering components have fresh grease.
I drive Ol' Roy all over town and mostly on the interstate. I can let go of the wheel at high speed and it tracks straight as a die. Going over bumps doesn't send the steering wheel all over the place.
Before I replaced the shocks and tires, it did bounce all over the place while driving.
What size and type of tire are you using? Bias plies will wander.
