Thank you very much. Tomorrow afternoon I will test it and let you know what the pressure is at idle. I was thinking that the sending unit may be going bad but wasn't sure. And also I was wondering what the service pressure is on this engine.
It can be done in the car with normal hand tool. Will take 4 or 5 hours on your back if you never did it before. I would check main bearing for wear if you take pan down. More ofter than not the low oil pressure is caused by worn bearings,