Vintage style split P bass pup with strong low end?
I'm kinda new to P basses so I apologize if this has been covered elsewhere and I just didn't find the info. I've got a Road Worn P bass that I'm pretty happy with except that the sound thins out below low A on the E string. You can still hear the notes but they lose that nice girth that P basses are known for. I've tried several different kinds of strings and even swapped a different neck and bridge onto the bass, but it didn't help. I'm assuming that the pickup is the problem. This one is wound on plastic bobbins, so it's not a Fender '62 pickup that has come on some of the Road Worn P basses. This is probably a generic MIM pickup or some sort.
I definitely want to keep the old school vintage style sound rather than a modern edgy tone. I can't afford to just buy and sell a bunch of different pickups trying to find "the one", so I'd appreciate some guidance to narrow down the candidates. Are there any that tend to have a stronger low end without getting muddy?
If it weren't for my wife, there'd be no adult supervision at my house...