the front wheels are leaning at the top and it wearing out the inside of the tires.
what causes the front wheels to lean in at ? on 1992 Mercury Sable
agree with bak it could be several items but alignment will let you know what is bad
1 more answer
This is usually a suspension issue which causes an alignment problem. Usual suspects are: worn ball joints, worn out struts need to inspect to find out which. Betting on the worn out ball joints.