Do you have an A/F guage?

But anyways, it went from running very very rich and you replaced the o2 sensor, and now the pump doesnt deliver fuel after 4k? Get more specific with that problem. If its what Im getting, you shouldnt be floorin it if its leaning out completely. You say your pump shuts completely off, but the car keeps moving after 4k? I dont understand whats goin on dude...