OK, the pressure sensor is on the back side of the engine, drivers side. You will need an oil pressure socket to replace it. The picture below will help you identify it. Use some thread sealant on the threads of the new sensor. I hope you have small hands because it is a bit of a squeeze. If you cannot get at it, you will need to take the intake manifold off, but that it not to bad either.
how do you remove the intake manifold ?