Low oil pressure
I own a 2008 chevy suburban Z71 5.3 flex fuel 140k using 5/30w oil. I have
replaced the oil pressure sensor twice and sensor filter and have recently
replaced the oil pump. One day after the pump was replaced low pressure
at the gauge only at idle once I drive it goes up stays at 40 or slightly over
come to a stop and it drops. No noise no chatter from lifters drives with
plenty of power
Since you have done everything I would suggest I think the engine is loose from wear. The only other things you could try is heavier oil such as 10W-40 and to try a mechanical oil pressure gauge to see what the oil pressure really is. A high volume oil pump might extend the life of the engine if it is loose.
Thank you I will try that next Ill run a gauge first and check to see that its not the gauge if pressure is low Ill try switching out the oil
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