My Fender Strat MIJ E series, has a really weak top E, picking notes on the string sounds ok, but any kind of hammer on or legato is very weak and doesn't ring out at all.

I have altered the pickup height by turning the screws either side of the pickups but still no joy.

Is there anyway I can fix this?
My first guess is the string is striking a fret and isn't ringing out clearly.

Does every fret have the same problem? Open string?

Is this a new problem?

I'd give it a full setup starting with the bow of the neck and see what happens.

Could also be a dead string, how old is the set you have on?
Ibanez RG1570 Prestige
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
Thanks for the reply

Every fret is the same, open string sounds ok.

I had it setup a few months back and a pick up replaced - past few weeks the string has gone really quiet.

Strings are fairly new.