Started the truck up this morning and pressure gage never came up and "check gages" light stayed on. I shut the truck off and tried again. Pressured up as usual, but then went to 0 later. When I shut my truck I can pop my hood and hear oil draining back to the pan. Is there a easy way to tell if my oil presure sensor is gone? I went ahead and drove . 75 miles to church and back and everything seemed to be going alright. (EGT, water temp etc. ) I did check and there's plenty of oil.