I recently drove back to Colorado from Texas, about an 18hr drive. I started out at 26.5 mpg then slowly declined to 22 mpg over the course of the trip. At home I cleaned the EGR tube which was not what I thought very dirty then cleaned the MAP sensor which was plugged. neither of these helped...
I have bee using about a quart of oil every 3-4 weeks. and cannot find out why. another problem is I am in Colorado and cannot get Rotella T6 anywhere.
any ideas why the oil usage?