I was driving home a short while ago and when I looked at my oil pressure gauge (Autometer Ultra-Lite) it went to zero. I was only about a 1/2 mile away from my house and managed to get home. I checked the gauge and wiring to the sending unit and tickered with it a bit and still no pressure. I just took off the sending unit and the shaft the it goes on inspecting it for clogs etc. and have found none. There wasn't that much oil in either the shaft or the sending unit. I also pulled the distributor to make sure the oil pump shaft hadn't broke and it seemed to be alright. How do I check the pump? Is there any other problems that might of happened?