I have a '94 P/J that I bought real, real used for $129 off the Interweb - might be my favorite neck of any bass, but electronically it is the single most frustrating device I have ever owned.
I want to love it - it's light, comfortable and the satin neck is unbelievable, but it was wrought with pickup issues when it arrived. They were noisy and lifeless - maybe half the volume output of any passive bass I own...and I had a grounding issue somewhere.
Turns out that someone had swapped out the original Peavey P/J set for a set from a Squier and only one-half of the P worked and the J was lifeless.
I swapped in an old EMG P/J set and it still was noisy/buzzy (which goes away when I touch the bridge - a pretty clear indicator that the bridge grounding wire is faulty). I shielded all the cavities with copper tape, put in new Fender 250k Pots and Cap, new Switchcraft output jack and all new wiring (including a new bridge ground). Still noisy and the grounding issue is still driving me nuts.
I bought a custom hand-wound P/J set from a guy in Philly and they exhibit the exact same issues. Low volume output and pretty thin sounding.
As an experiment, I direct wired both pickups and the bridge ground to the output jack - basically eliminating the V & T pots. They sound good - full on V & T (not my cup of tea) - but I still have the grounding issue. I think I've replaced and repositioned that grounding wire and bridge 6 times now and have resoldered everything a few times and I still cant get rid of the grounding issue. Once I do, I will love this bass - and by the time I'm done, it may have only cost me $1k - I kid, I kid...
Sorry for writing a book - needless to say it's a work-in-progress.
Here it is next to my '90 Fury: