Anyone else notice a vast improvement after your first oil change????

I ran the last tank with NO CRUISE, Close to posted speed limit and got 33.5 MPG at 447.7 w/ 13.365 gallons of fuel. Tank prior was 27.5 MPG Changed oil at about 4,000 miles. Onstar said I had 75% oil life, but with the initial break in I decided to not wait any longer.

Opinions??????



Dundertaker