only way to fix a dead spot is get a new neck.
Well, that's not necessaily true. Deadspots can result from three main factors, as I've been able to figure:
1. Poor fingerboard to neck vibration transmission, either due to some "flaw" in the fingerbaord or the neck wood, such as a knot (this one is bad from a fix perspective) or glueing problems;
2. Headstock to body mass ratio; and
3. Neck truss-rod profile.
In the case of #1, you've likely got to walk away from a sale, or if you own one, it's not a terribly good situation. In the case of #2, there are a number of easy fix tries, but they'll cost you a bit of $$. In the case of #3, a minor truss rod adjustment can redistibute tension on the neck to fix this, but this situation is typically observed on basses with dual truss rods like Rickenbacker.
I have a number of electric basses, and I've noted problems in two Fenders, a Warwick and a Rickenbacker.
Fender deadspots are on the G string between C and E;
Warwick deadspot is on G string E; and
Rickenbacker deadspot is on D string B and/or C.
Since so many Fenders have this issue in the same location, #1 above is not likely the problem. Try reducing the weight of your headstock by removing the E tuner and the E string. See what happens on your G string.
If it improves, get a set of lighter tuners to reduce headstock mass. It has worked for me. Alternatively, a higher-mass bridge might accomplish the same thing. It's all about mass ratios between headstock and body (well, it is
if that's the problem).
If that doesn't work, try a very small tweak of the truss rods (either direction; experiment here). Even if you don't have dual truss rods, sometime just relieving pressure in a small spot and redistributing to another can help resonance, which is what you are going for. You may get lucky and send the deadspot a few mm to a spot that isn't critical to a fretted posiion.