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When you changed out the Oil Pressure Sensor...Did you also use a Pick to extract the Old Oil Pressure Sensor Filter Basket buried (submerged) directly underneath it? If not... This Link to RockAuto is where to get a Brand New One that will probably solve this Low Oil Pressure Issue since they tend to collect a lot of Black Carbon Mung that will prevent the OPS Unit from sensing pressure correctly:
RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.
www.rockauto.com
Barring this action... you can also install an Analog Oil Pressure Gauge via the External Oil Pressure Feed Port located on the Front, Driver's Side of the Block and Thread In an M16 X 1.5 Metric to 1/4" NPT
(Nat'l Pipe Thread) Adapter and run a slender White Nylon or Copper Coil Line through the Firewall and into an Analog Oil Pressure Gauge via this Kit:
Dorman's Engine Oil Pressure Gauge reads the oil pressure of the vehicle and is universal to fir most vehicles. The Engine Oil Pressure Gauge is manufactured from high-quality materials for long-lasting durability.
www.ebay.com
Several companies sell this M16 X 1.5 X 1/4" NPT Line Adapter:
The lack of oil pressure ports available to feed a turbo system, oil pressure gauges and oil temperature gauges is an LS engine swap issue that often gets overlooked in the beginning. Factory engine blocks have no provisions to accept a standard NPT fitting, making it a common issue that needs...
lsxinnovations.com
Of course...It follows on that Changing the Oil Filter and Motor Oil to Quality Products like using Mobil1 5W-30 Engine Oil and a Mobil1 Oil Filter should be THE priority action to take...
BUT ONLY AFTER ...You First Drain the Old Oil and Toss the Old Oil Filter and install a Cheap Oil Filter and some Cheap, Organic 5W-30 Motor Oil along with substituting One Quart of ATF and then running the Engine briefly to clean out the Motor Sludge.
THIS is the Best Course of Action to perform BEFORE using the Quality Mobil1 Products and then ONLY AFTERWARDS... replacing that Oil Pressure Sensor Filter Basket...
lest it become clogged up all over again.