Hey, I have a Peavey Grind 4 . I tune my low E string, but it wavers around and never really stays at one pitch very well. Well enough to play and all, but not nearly as perfect as the other strings stay. It stays about the same Tune-wise (always *around* E), but it never is DEAD on without going flat or sharp a little. I don't touch the string, and all others are muted. What can I do to fix this? I searched a little and didn't find anything, but I may have just searched the wrong keywords.