Before I say anything, let me scream: MY IN-TANK PUMP IS OPERATIVE! That's what makes this whole ordeal so frustrating.

I love my Volvo. The only thing I love more than my Volvo are my family and the Lord Jesus. I DON'T love that I'm having stalling after starting issues and incessantly annoying main pump noise despite having replaced a good majority of the fueling system.

The stalling only happens sometimes, and only right after I start the car, preceded by a couple of seconds of the sound and feel of the engine struggling to get (what I assume is) fuel. It seems to only happen when I try to start the thing after the engine has warmed up. My car does not give me any codes (I've checked twice), and the only time that the Check Engine Light comes on is right before it stalls. Once it gets going, it drives absolutely fine, sans some small idle issues.

The main pump noise doesn't care how full my tank is. When I turn the ignition to 1, you can definitely tell that the main fuel pump responds because it buzzes at you angrily for a couple seconds. I am starting to hear the unpleasant buzz of an undulating, angry bee vortex when I lay down to sleep at night.

So far I have replaced:
-Both the main and in-tank fuel pump (they are both Delphi)
-Fuel pump relay
-Fuel filter
-Fuel presssure regulator
-All fuses
-Distributor cap and rotor

I've also cleaned the throttle body and checked under the hood for vacuum leaks. No fuel leaks, either. Spark plugs and wires are fairly new.

Please, help me find a solution before I go insane and ruin some poor nurse's life murmuring about fuel pumps in a mental hospital.