I've wondered about air in the oil line to the pressure gauge myself. Then the oil pressure on that particular engine was reading around 30 which is about normal. I've just assumed that the air compresses and there is some small error.
Worn bearings have more clearance for the oil to squeeze by so you loose oil more quickly. Another way to look at is if you hold a garden hose flat against a wall. The closer it is to the wall the more pressure you will feel.
You should be able to bleed the air out. Disconnect the line from the gauge, pull the coil wire or,,, then turn the motor over with the starter till the air is pumped out. Reconnect everything and see if there is a difference in oil pressure.
It wouldn't hurt to drop the pan and check things out. Then again you might not like what you find.
I'd baby it along and look for a replacement.
LG
LG
