My '97 Z34 fuel pump is noisy. Been that way since I bought the car last month, so not sure if this is typical of these. The car has 78K miles. It makes a whining noise, louder than any other car I've owned.

How difficult (expensive) is the pump to replace by a repair shop?

 

Check your fuel pressure, if it's good then you should be fine. My stock pump was loud, but it will likely run you a good 400 bucks in labor.

 

Yep, mine is pretty loud as well. 134K miles on what I believe is the original pump (bought the car three years ago with 116K miles).

 

Is the pump inside the tank?

 

Yes the pump is inside the tank, so you need to drop the tank to get to it.