The oil pressure gauge has been actin up in the rab for a while now. It would be fine, then drop, then be fine again. Bounce around randomly and what not. Never went to the High side of the gauge tho. Now, its dropped (comes up a little once n a while) but stays down. The Oil light is on whens its dropped everytime, and is now on constantly. Now here's the thing. The Truck runs fine, no knocking, nothing. Could it be the sending unit? Or could the pump be on its way out? I'm planning on going to pick up a sending unit this evening and hope thats all it is.