Ive aligned quite a few jeeps to pretty good accuracy. I took it to the pros today so that they could take a look at my tires and give me some documentation stating if 1 or more of my tires are bad. Its allways something.
I've only done a couple of string alignments, but I've never had one dead-on accurate. I'd be surprised if anyone would fault the tires before you have the alignment checked on a machine. Not saying your alignment is bad, just that it can't be ruled out. Pulling left or right is a classic alignment issue.