Steering Probs.

First off I have tried the cheap step rotate the tires. Everyone asks that of course. Well the prob seems to be. while driving teh steering wheel puls from left to right not a whole lot just about 2 inches to the side then goes back to the other side like a shaking motion and you can feel it in the car also while driving it. Going over 50 it seems like the car is going to pull itslelf off the road. It has been like this for quite a while now just havent ahd the time to get it fixed. Now since I have a kid my family of 3 cant hop in the truck anymore if we have a trip to take. I had a at home mechanic look at it and he told me the rotors are warped and one of the outer tire rod ends are loose. I just dont know though wouldnt the rotors just effect it while braking if they were worn?????? Just wondering I am an aircraft mechanic so I know a bit about mechanics, but dont know a thing about cars really so if anyone can help or has an opinion id be grateful. Thanks