I'm running a red Radio Post servo for the steering in the 1/8 scale nitro buggy. It used to track very very smoothly as it turned the wheels side to side. Months later, it isn't smooth at all. It's actually rather jerky. It still works, but it doesn't seem to be able to hit an infinite number of points along its path. It seems like it only, as an example, hits 10 points. If I turn my controller's wheel (4PKSR) it jumps from point to point, thereby making it not smooth. What does this mean?

Most likely the potentiometer is going out. Time to replace.

This is also common from not having the epa's set right and over time burning out the servo