2002 Nissan Truck inconsistent wobbling

Thanks, Mark. Really appreciate any help I can get here.
I don't think it has one of those steering dampers, but don't really know. The Nissan place didn't seem to think it did, but that was just the guy up front. They said the tie rods could stand replacing and it needed alignment, but it had recently been done twice already. I took it to another guy, and he said tie rods and ends were fine, and I think he said he checked the ball joints too, and said he couldn't see any problem, and thought it was just the cheap tires I had. These only had ten thousand miles and were wearing out of round. I got brand new higher end tires, and it was much improved for a day or so. It is slowly going back to a strangely inconsistent, worsening wobble and pulling to the right problem. The steering wheel just barely shimmied at first on the new tires, with no real truck shake. It is strange how it seemed to get worse gradually during the week after getting the new tires. It was cold and wet here this morning, and I don't know if it had anything to do with it, but it seemed even worse than ever today. It was like it was before buying new tires, where the whole truck would even shake sometimes. That's part of the inconsistency here. The truck sometimes shakes, and sometimes it's just the slight wheel shimmy. Thanks again if your able to offer more advice!