If you try adjusting the shifter cables, here's how:
1. remove the shifter console by unscrewing the four 7mm screws under the ashtrays, the shifter knob, and lifting it off.
2. have a look at the picture below and you'll see that I've stuck a small screwdriver in a hole on the side of the shifter mechanism. The screwdriver goes through two or three holes that all have to align and will go all the way through to the other side when the shifter is properly placed in third gear (if I recall correctly). Use anything that will fit, and pin the shifter into place.
3. Next go to the tranny end of the cables: If you've got a Getrag, then the only cable that's adjustable is the cable on top... just loosen the nut and let the cable sit where ever it wants on the lever, then tighten the cable nut again. If you have an Isuzu, then do the same for both cable nuts since they're both adjustable.
4. Once you're done, unpin the shifter and try it out.