You're going to have to describe what you're getting better than that.

IMHO (in my humble opinion :-)... when mileage is getting that high, a little extra warm up time is required to get all fluids circulating, etc before taking to the road AND a good quality oil is essential. Others may differ but for my money, Mobil 1 synthetic is the way to go. Could just be a lifter noise but again, if after a good warm up the noise goes away, it's likely mileage related and all the more important that you warm her up good before taking to the road.