This is pretty annoying. Any time I use the vibrato on my Strat, the low E ends up sharp. If I really drop the pitch with the vibrato, it comes up a full half-step sharp; it's almost a perfect F. When I grab the string and pull on it, it'll drop back down to E, but that's not exactly ideal. And it's happened with the last two low E strings I've had on this guitar...I believe they were even different brands.
I assume the nut is grabbing it, taking up the slack when I lower the pitch, then not giving it back when I bring the pitch back up again. But I always put some of that Big Bends Nut Sauce on the nut when I put the strings on. Could anything else be causing this? The bridge?
Would it help if the string didn't break quite so sharply over the nut? Maybe I should try winding the next E string I put on upwards on the tuner shaft instead of down.
Maybe I need a new nut. In addition to this tremolo problem, I'm still having a problem with notes fretted on the first few frets being too sharp, no matter how gently I fret them. There's a luthier in the next town over; an authorized Fender service guy. I might just take this guitar to him and have him install and cut a new nut.
If I did that, what should I go for? Bone? Graphite? How much does a new nut cost, generally speaking?