I have a Malpassi Rising Rate fuel reg, and get an intermitent whinning noise from it. I could go 2 or 3 tanks with no noise and then all of a sudden it whines, under a little load or a lot of load. It doesn not matter what fuel i use, or how full the tank is and just as quickly as it comes it wil go.

Any ideas?

I am running a 650hp bosch motorsport fuel pump and larger injectors but cant understand why it comes and goes.

You're not getting any fuel leaking into the vac line?

Is the manifold in boost or does it happen at negative pressure as well?