I have a 2002 GMC Envoy and the oil gage keeps dropping to zero.
Make sure that the oil level is at the full mark. Is the engine making any noise like a ticking or knocking? If it is then most likely the oil pump has failed, do not drive, if you do it will ruin the engine completely. If the engine is quiet then check the actual oil pressure with a manual gauge, if the oil pressure is good and stays steady then it is a possibility that the oil pressure sender is going bad or the gauge.
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