I changed the oil a week or so ago, going from regular to Mobil 1 Synthetic 10w40, seemed to be regular pressure then, maybe 15 at idle warm, right up past 40 with a tap of the gas, now (today) after driving for a little bit, the oil pressure drops to maybe 8-10 at idle, and under load it only raises to maybe about 35,

Pull the motor now or drive it till she pops? Maybe try thicker/thinner oil?

-Mark