I will be more than glad to let you know that imperfections in the road can and will cause vehicles to track. In my area lots of roadwork being done, so lots of cracks, potholes, repaired sections, patches, divets, filled in gouges. I don't notice it much in my 4Runner with 285/70R17's but the vehicles I work on tend to follow those imperfections more. Its not so much a matter of tire width as much as tire flex and squish. I notice that the stiffer and skinnier the sidewall, the more that car wants to dive into ruts, buck against any imperfection in the road, and overall not track right.
Camber and particularly caster can play important roles in the tracking of a vehicle. Think negative caster; like a shopping cart wheel, how it doesn't really track straight and wobbles when you push the cart, compared to positive caster like a bicycle.
Back to the OP; I have a couple questions. What tires are you running (size, make, what PSI are you running?), did you get a chance to look at all your bushings and linkages? Do you have any problems with your power steering? Also, how severely is the vehicle wanting to track? like pulling to the right or left sharply or almost turning the entire wheel a revolution or so? When it does occur, are you on rather rough bumpy roads going at a moderate speed? Is the Traction Control or ABS kicking in at all during these times?
Thanks everyone for the help. The tires I'm running are the stock dunlops, at the tire stamped psi I would assume. The dealer just put them back on on. The power steering works great. The abs does not come on. The vehicle wanders mostly while riding on rougher than normal roads. On good roads/interstate the vehicle rides great and does not wander, just a slight vibration which is due to tire balance I think and steering wheel shake/loose front end feel over bumps. The biggest problem is just when riding on rough roads which are most of Vermont paved roads. Going over rough roads the front end feels loose, wanders a little but definitely the biggest issue is the vibration and "loose feeling". My Tacoma never felt like this.
I will specifically ask the dealer to check the swaybar bushings, linkage, and suspension again. I would think that it being a certified pre-own toyota they would have checked all of this.
Thanks everyone for the help.