Just thought of something else... I had a Nissan 300ZX Twin Turbo maby years ago (fast, but horribly unreliable an miserable thing to work on) that did almost EXACTLY what you describe. You could take a fuel line loose and the pump would shoot am unbroken jet of fuel four feet. Problem turned out to be the pump was producing NO pressure, even though it produced volume and you could hear it running. Check fuel pressure.