can anybody tell me how to properly adjust the chokes on a 93 indy xlt?

You should be able to pull up on the sheath 1/8" before taking up the slack. The choke cable should slightly loose when in the off position.

What I did on my '94 XLT was to screw the adjusters out on all three choke cables until there was about 1/4" of play in the choke lever when it is in the off position, and then back one of the cable adjusters off until you get about 1/8" of freeplay in the lever. Then back each of the other cables back in until you can feel each one start to reduce freeplay below 1/8" at the lever, then back the adjustment back out to 1/8". Snug the jam nut on each cable so the adjustment doesn't come loose.