There is a spring on your shift linkage that causes the stick to always center itself in the shift pattern as everyone is used to. If this spring is worn out, or the pear-shaped washer (which one end of the spring is attached to) has rotated, it will cause the stick to spring back to a strange position. In my case, the washer rotated aft, and the stick was always returning to the full right, caused by the tension increasing on the spring.... i only imagine yours is caused by a broken or worn out spring, which would cause it to go to the left. To fix it, you have to drop the center section of the exhaust and remove the driveshafts to access the shift linkage. Probably not worth it.