Hello, my 80 fj40 is running fine this 6 year, no trouble at all, change the oil a couple times. But last week, i change my oil and when i drive it, it had no oil pressure. After couple minutes it comes up and stay at 3/4 like always. Now after a week, when i start it, it got no oil pressure again and didnt come back, what when wrong with my cruiser guys? You guys ever come with trouble like this?