What would cause the water pressure gauge to jump between 20-30psi non stop? It worked fine at first, but then started acting up. At idle it shows 0, but then running she bounces back and forth between 20-30. There was a lot of debrise in the water from heavy rain, so I imagine I sucked something up. I am getting good water pressure...steady flow at idle and running, so I know its not the water pump which is brand new anyway. Has to be the gauge or something stuck somewhere. Thanks!!