oil gauge

[michael 52]

I have a 2004 tahoe with a 5.3. when idling oil pressure gauge maintains 40lbs when revved maintains 60

lbs when driving sometimes gauge bounces all over and makes the no oil pressure chime ding. Does not do this all the time. have replaced oil sending unit and dash cluster and still have the same problem. have made several trips of 250 miles each with no problems or knocks can you advise?

[gmtech4]

i have no idea,,,,heres a schematic fo ya

 

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Gauges