1993 Explorer vibration

I have a 1993 Explorer, 2 wheel drive, 4 door with 162k miles on it. It has been taken very good care of and I have no problems except for this one. I am getting some pretty severe vibration from the passenger/front tire. I have moved all 4 tires around and replaced the calipers and wheel bearings and the vibration continues. Occasionally I would have problems with my ABS so I unplugged it but nothing has changed. I am completely stumped. Any suggestions would be greatly appreciated.