99 ranger vibration

hi, I have a 99 ranger 4 cyl with 35k miles. everything looks new and it drives nicely. I have noticed that when I drive over 60 mph, I can feel a vibration in the steering wheel (the wheel vibrates left and right). sometimes it vibrates, sometimes it doesnt. I have rotated the tires every oil change, and the tires are balanced. it vibrates when I'm driving down a straight interstate with even pavement. I have heard that this might be because of a bad upper ball joint. I havent taken it to a mechanic yet because I fear that they might not fix the vibration.

also, I have noticed that when I go over bumps in the road, the truck bounces like it has no suspension, is this normal for ford rangers?

Honestly man, First things first easiest way to sum these things out is to start at the basics, Check your wheels, are they aluminum or are they steel. If they are aluminum you could be suffering from a bent wheel, next I would check the tires, see if you see any really uneven tread wear on the inner or the outer portion of the tires. If you see a lot of chopping on one side and not so much on the other side you probably have a front end suspension problem. However I recommend you go find a mechanic that you trust this seems to be a problem that I or one of my mechanics could locate in a matter of minutes... Good Luck to ya hope this got ya started.