Why would the speedometer on a 1995 Pathfinder work some times and freeze other times?

I have a first generation Pathfinder (1991) and the needle has contacted the face of the speedometer. I drilled a small hole in the plastic and used a small wire to bend the arm from touching. jimbolyard@yahoo.com My mechanic said that my speedometer cable ('95 Pathfinder 4wd automatic) had stretched. Since this repair was over $200, I opted for the quasi-fix: I hit the trip reset. This gets the speedometer working again about 75% of the time. It's been this way for the pass 3 years and has not gotten any worse.