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You likely have a oil pressure switch starting to fail........Its up to you if you want to replace it now or wait to see if it continues to happen....Its a cheap part and a quick fix......If there was a actual oil pressure problem it shouldnt go down and up like that. It it was a electrical problem other then the oil pressure guage itself other symptoms would have happened so I wouldnt be too worried about complete electrical failure. Let me know if you have questions, thanks.
The sensor is right above the oil filter, here is a picture. Let me know if you have questions. Thanks.