Uneven grass cutting

I have a Troy Bilt 42" cut riding lawn mower and have a problem with uneven cutting of my lawn. I have adjusted the deck but still have the problem. It seems that the deck moves unevenly when making turns or over rough terrain. Any suggestions on how I may correct the problem

Start by checking the air pressure in the tires. A low tire will cause uneven cutting in turns, especially if the low tire is on the outside of the turn.