I have a 2007 suburban 5.4l with 130,000mls. I have had to replace the Oil pressure sensor before and just did it again, this time it did not fix the problem. When I start the car up the oil pressure goes up to normal for about a minute then slowly drops to around 2 PSI and all the alarms go off. What could be the problem?

 

Could be oil pump.
verify pressure with mechanical gauge.