1987 bronco II losing oil pressure

Help guys my bronco II starts out cold with 40 psi of pressure, only to drop steadily as the oil thins all the way down to 10 psi. Please any thoughts on what this might be? Pump? Clogged screen?

Welcome to AF!

If it was the pump or screen it would start out with low oil pressure, too. Most likely, the bearings are worn out. Try a heavier oil such as 20-50 or put in a can of STP.

Thanks, I put a gauge on it and idling it holds at 10psi when I accelerate it holds at 30psi. How is this?? Good or bad?

If this is after it warms up it is not too bad. If you keep the motor running freely and not under an excessive load it should be all right. I think the light comes on at 5 lbs. so you are well within that limit. With as many miles as you have on it, a heavier weight oil shouldn't hurt your gas mileage. It a newer engine it would cause drag, but I don't think it will in your case.