I have noticed that my 06 pulls to the left. It all started when I put a diff. and larger size tire on. Could the diff. tires cause this. I have never hit a chuck hole or anything to cause a miss alignment. The factory tires worked great. Does anybody have any answers? By the way. The tires have 50# front and the rears 40#.

 

Try swapping tires side to side as sometimes certain tires can cause a tire pull. This is possibly the case as you say it started just after installing the tires. What brand and size were the tires? If you swap the RHS tires to the LHS and the car pulls the other way then the only way to fix it is replace the tires.