[rsmith8411]

Here are the answers to some of your questions:

1. 5.7 L Vortec, K1500 4wd
2. Just replaced the fuel filter after reading your post (no change to symptoms)
3. Fuel pressure: key on, engine off -- 60 psi; engine running -- 52 psi
4. Didn't check the wiring since this would involve dropping the fuel tank. I suspect that is what is causing the flutter on the gauge. I can live with that for now.

With the fuel pressure test gauge attached, I can hit the pressure relief button on the gauge and the noise stops momentarily. I am almost certain the issue is the fuel pressure regulator. I'm going to replace it, which looks like several hours of work. Am I on the right track?