Need help identifying part to replace (tie rods, arms, struts?)

We can't do it from here. You need a visual inspection and test to confirm what requires replacement.

Sorry, can't do that over a computer but it's good you noticed the problem before something breaks and sends you into a tree or oncoming truck! Have the steering and suspension systems inspected at a tire and alignment shop. Some offer free inspections and if they aren't real busy they might allow you under the car where they can show you how they inspect the parts and determine if they're okay. It would take entire pages of typing to explain how to check each part. It's way more involved than a simple visual inspection. I'd be happy to explain the procedures if you suspect one or two specific parts, but you'll need a helper, jack stands, and a pry bar.