The 3rd door, or "operable panel" on my '99 S-10 rattles quite a bit when driving on bumpy roads. It's definitely coming from the upper latch area. I imagine this can this be adjusted to reduce the rattle, but how is it done? I'd rather know what to do before removing the interior panels, they never seem to go back on right.

yea, sucks doesn't it
i have 97 w/ same prob.
i took door apart lubed everything up.
yes you can do some adjusting, but i think its a bad design
panel on third door just pops off. remove seat belt bolts first than it will come right off, and expose all your looking for