After some spirited driving, the next day I changed the oil and filter and noticed a lot of oily residue on the bottom of the oil pan, making me think it was most likely the crank sensor o-ring or pan gasket, but...when sitting, the car was dripping liquid towards the driver's-side. Turned out to be a power steering fluid leak; inlet and outlet tubes and clamps were replaced and all is good for now. $415

Greg