if you hasve any reason why this happens and how to fix can you please explain to me. thanks for your help

 

replace all parts that have play in them

 

Steering box
Tie rod ends
pitman arm tie rod end
wheel bearings
bad tires

Check those 1st

 

bad alignment?

 

A bad alingment shouldn't give you excessive play in the steering. It would however cause wandering if the toe is not set correctly.

 

Its very common when u add large tires and put the steering box under strain that it will develop play. I don't know of a way to fix the problem other than replacing the steering box.

 

I didn't notice that yet with my 32's but good to know.
I got the Rusty's steering brace on mine but that is supposed to help prevent the unibody from cracking with oversized tires. I don't know that it will help with any "play though"

 

arent the steerin boxes on xjs adjustable for wear?

 

Yes, there is a write up somewhere for it too!