car suddenly pulls to side on 2002 Mercury Villager

When driving the mercury villager suddenly pulls to the side then corrects after new front tires and new alignment.

3 answers
So the problem is no more? Or, is it still doing this? If so, there are a few possibilities like a failing brake pad, bad wheel bearing, or, the alignment was shunted by hitting a curb/bump/rr track/etc....
Check Tie Rod.
It could be loose popping in and out of place.
switch tire left to right see if it still pulls