I have noticed when I start my 98 Astro with 210,000 miles my oil pressure starts at about 46lbs and it increases to around 60 with acceleration. Within 5-8 miles the pressure drops to around 10Psi. if I am stopped at a traffic light my check gauges light comes on and and the pressure will have dropped into the Red area. The van has had 2 oil/filter changes in the last 500 miles and only synthetic oil has been used for the last 100,000 miles. Is this an oil pump problem or am I losing pressure due to the engine being worn out and blowing past the rings????
Questions????
Comments!!!!

P.S.
After an hour the pressure returns back to 40 plus upon start up and again drops like a rock with driving

 

Try a mechanical oil pressure gauge to see if you are getting accurate readings. Blowing by the rings won't give you low oil pressure like that. It will make it smoke. More likely that the main bearing or cam bearings are worn. It could also be the oil pump as you stated.

 

I was taking a guess about the rings. There is NO blue smoke and the oil level is not dropping.