OP's problem sounds more like a faulty switch/loose wire than anything to do with low pressure. His motor would be done by now if that was the case, or at the minimum starting to make some funny noises.
You can test it by hooking an oil pressure gauge where the oil pressure switch is and turning on the motor. The oil pressure will always be high on start up. Cold oil is less viscous and therefore pressure is going to be higher. As it warms, the pressure will drop.
The manual does say no less than 10PSI at idle and no less than 50PSI at 3k RPM as k20wagon mentioned. Mine is 90psi on start up, and ends up at 15 at idle after its warm.