How do I fix loss of power, rough idle, and eventual engine shut down?

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I have a 2000 Audi a8 with the 4.2 V8. I was driving along last week and everything was fine and suddenly I lost power and the RPMs went to idle, when I pushed onthe has pedal, the RPMs would drop, and I had no choice but to pull over. When I stopped, the idle became rough, and the engine began to sputter then died. The engine would try to start to no avail. I diagnosed the problem as a bad fuel pump and replaced it. After the new pump was in the car started right up and ran fine for a few minutes, but then it started sputtering and died again, and won't start again. Shortly before the the problem originally occurred the check engine light came and I ran the codes and it came up as a bad mass airflow sensor, and temp sensor if I remember correctly, but I was very busy and didn't have time to change them. Could the problem be the sensors?