Truck pulls to left or right

Prerunner pulls left or right, Depends on what it wants to do. If I let go of the steering wheel you can see the wheel move to the left and right quickly almost as if it's really sensitive to the road. Sometimes the truck will veer left and sometimes right. When I test it out I am an straight flat roads. It's annoying I bought the truck one month ago it's a 2012 Trd sport with 265/75/16 cooper discoverer atp (which I hate) with mb wheels. I got an alignment, they said it was off because it pulled only right, now after alignment it pulls left or right. I'm going to take it back to dealership but any suggestions? I jacked up the front and did the 3-9 and 6-12 position and tires are very tight.

 

Is it stock? No lift? If it were me I'd want lower camber(0) and higher caster(2.5ish).

 

No lift or anything. I know it came with 17s from factory but now it has more tire and less runs with 16s which I like better but don't think there's an issue there. Thanks for the advice someone I know said the toe is off in the rear but I don't know

 

Yeah the rear seems farther off than normal, but there is no adjustment for that.

 

Sounds like caster. Tires will follow the angle of the roads and crevices in the pavement if the caster is too far off.

 

Yeah that's what it seems like it's doing following the road.. Too much. Thanks will update once I take it back