Hookalatch - There's no oil filter on my truck, but, nevertheless, you have a good point. Even without a filter, it still takes time to fill the oil galleries after they drain back to the pan. I suppose this could explain the slow pressure after the truck has been sitting idle. It's not a priming issue, but rather it just takes time to fill the oil passages before I see pressure at the gauge.
The oil passages are very clean. The engine was completely re-built except for the oil pump (my mistake!). I cleaned and inspected the pump before re-installing it in the engine. The pump basically looked so simple and bullet-proof I didn't suspect any problems.
I certainly don't want to replace the pump unless I know it's defective, but I'm also terrified of running the engine for more than 5 to 10 seconds without oil pressure. Maybe a few others will respond and let me know how long it takes to develop pressure in their engines.
