Oil pressure slow to build

Hello, There are a few different possibilities, and testing will flush out the right one. The oil pressure sensor may have failed, the oil pressure gauge may be failing, or the oil pressure may actually be low. Testing the oil pressure with an oil pressure gauge connected to the engine will let you know the issue. If the oil pressure is low, you may have engine sludge, a bad o-ring on the pickup tube, or a failing oil pump. If the oil pressure is right, the gauge or oil pressure sensor may have failed, so you will have to test the sensor. If the sensor is good, the gauge or wiring is faulty.