You may have your front and / or rear wheels toed out. Toe out makes the car darty, and will make it follow patterns in the road surface much more than if they are toed in. How long has it been since you had it aligned? Did you lower the car and not have it realigned?

 

Your rear tire pressures are uneven (or your tire wear is uneven).

Try this:

Accellerate. Does the car will pull one way? Now let off the gas. Does the car will pull the other way? This is what happens if your rear pressures are uneven. If your fronts are uneven, the car will just pull one way no matter what.

In the future, keep an eye on this - it's not good for your differential to have to spin the wheels at different speeds all the time (due to the difference in circumference).

 

[QUOTE]Originally posted by matt_inva
[B]There is always the possibility that you road that you are on has ruts from heavy trucks.

 

This very simple, guys.

The more camber a car has, the more it wants to "jump around" (jump, jump j/k) because it takes less resistance to turn the fron wheels. And that's because the contact patch is smaller, among a few other things.