Actually, I also noticed a slight drop for the first tank following the oil change. And I did the change myself so I know it was done right.

Like you, after a few hundred miles it was back to normal. Several tanks since and I now have an improvement in mileage. But that's because I'm still learning how to drive this dang thing. It's more fickle than my wife.

Ron in SoCal

Saving the Dinosaurs . . .