Oil pressure Question: What causes this?

I was also going to suggest the filters. And I agree, run Wix. Any filter you pay less than $5 now a days is a POS. Napa and Carquest sell the Wix line, but make sure you get teh good one, not the cheaper line. The air in the line is no big deal. It compresses and the gage reads, then when pressure drops, it expands again.