What is the nominal fuel pressure?

Have you done any testing? Engine cranking, you have spark at the plugs and fuel injector pulse? Use a gage and check proper fuel pressure, key on engine off, 60--66 psi. The spider fuel system is noted for problems.
Any applicable trouble codes?

What fuel injection system does it have ? Center port fuel injection or fuel rail injection ? Are the injectors being controlled (turned on) by the PCM - engine computer ? Do you know how to test injector drives ? Injector driver is a transistor inside the PCM , that controls the on/off time of the injectors . How to test fuel injector circuit with basic tools open control wire How to change SPIDER INJECTOR on Chevrolet V8

You need to have the fuel pump pressure tested when this loss of power is present. You should at least 42 PSI and about 50 PSI under a load or when the throttle is applied quickly. The fuel pressure test port is on the fuel supply rail on the top of engine, it is a pipe that sits over the fuel injectors. The fuel press test port looks like a tire inflator valve.

Which fuel system do you have, spider fuel system or tbi? Check for proper fuel pressure. Check fuel injector pulse.

If you have the spider fuel system, that system is noted for problems. Any applicable trouble codes? If computer doesn't see an rpm signal, no injector pulse, no fuel.

I can't rule out a problem with ignition module, but, there could be other issues?

I would first do a fuel pressure test first to determine if the fuel is indeed doing its job. 4cyl. could be bad injector, 6 cyl has spider injector assembly and fuel pressure regulator which I would check the fuel pressure regulator after the fuel pressure test.

You are equipt with a CSFI injection system,most tech call it the spider injection system,these injector deliver fuel to the popet injector by a tube a plastic tube ,if this tube rupture there is no way for you to see it ,and plus if the fuel pressure is unstable you have a pressure regulator failure,not the fuel pump,dropping the axle has nothing to do with your problem or a fuel pump ground, it get its ground from the ECM, if it was a direct ground the relay would burn, If you want to solve this problem access the fuel pressure regulator and you will see leakage and inspect the injector tube,also check the motor oil and see if it is fuel contaminated.

or possible sticking spider injector need to do a injector balance test but they are common for bad fuel pressure regulators they are located inside intake on injector assembly

purchase a "noid" fuel injector tester from an auto parts store; it is a small light attached to a fuel injector plug unplug an injector from the wiring harness and plug in the "noid" to the injector harness connector you just removed; start the engine: if the "noid" flashes when you crank the engine you will know that that fuel injector has power to it, then: use the "noid" to check each injector in turn. if the injectors are good test the fuel pressure with a fuel pressure gauge; low pressure suspect a bad fuel filter.

a simple 12vdc will not due, it needs a pulse signal from the computer. a full 12vdc could fry the injectors, but the spider assemblys in them v6's are always a @$!$@ up design. i have encountered alot of them with bad pcm, or the spider.

Try a fuel pressure test. I once put a brand new from the dealer fuel pump in a 4.3/ When I had pressure, I then replace the injector spider in the vortec engine, to the tune of 500 bucks. I then found out that 10psi was not enough to engage the injector. It had to be 51psi or better. I replace the pump again and it worked fine. It was a hard and expensive lesson. If you do not have a manual for the vehicle, stop by an Advance and check out a Hayes manual. Section 4 on the first page will give you the specks for the fuel system.

Hope this helps.