When I drive, I move the steering wheel and nothing happens for the first few degrees of turn and then I encounter resistence and it turns. It's the same either way. The vehicle seems to track nicely, doesn't pull to either side, just a lot of slop in the steering wheel.
Is there a way to determine if this is really steering related or is it just loose/worn front end suspension parts making themselves known? My guess is suspension items, but the fact the front end behaves itself when the truck is moving has me doubting that just a bit.
The steering components would be the first place to look. Ball joints, tie rod ends, etc. If that all checks out, it could be in the steering box. Is your truck a 4x4? And has the front end been rebuilt before? I had my 02 done back over the winter for the first time with close to 140,000 miles on it.
Steering gear - they're a known/common issue. It can be adjusted via the allen bolt in the top of the gear, but that's a temp patch more than anything. A lot of members here seem to like the Red Head steering gears when they replace the worn stock part....
On top of the gearbox is an allen screw with a lock nut. You back off the lock nut, making sure to watch the allen screw. If it moves, then you need to move it back from where it was when you broke the lock nut loose. Then you tighten it about 1/8 to 1/4 turn, and tighten the lock nut, making sure the allen screw does not move. Then take it for a test drive and see if that fixed it. Before doing this, I would make sure everything else is in good shape. If you over-tighten the gear box you will create bigger problems.