Oil Pressure Test

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect and remove the oil pressure sensor from the engine.
Connect the Oil Pressure Gauge to the oil pressure sender oil galley port.
Run the engine until normal operating temperature is reached.
Run the engine at the specified rpm and record the gauge reading.
The oil pressure should be within specifications; refer to ENGINE - 3.9L & 4.2L .
If the pressure is not within specification, check the following possible sources:

insufficient oil
oil leakage
worn or damaged oil pump
oil pump screen cover and tube
excessive main bearing clearance
excessive connecting rod bearing clearance