I have a 09 Ford F350 CrewCab 4x4 about 100,000 KM i chipped it and increased my milage about 15 % or better , i do not use position 2 or 3 just keep it natural above 60 MPH fuel goes south. my normal truck weight is 9460 lbs or 4300KGs so i am always heavy. To increase my milage i went to 35 inch tires which increased my milage about 2.6%.
with the diesel and 35s there is no appreshial drop in torque or towing ability . Iam at 227,000 miles and still going strong.

Norm

There is not enough darkness in all the world to put out the light of even one small candle----Robert Alden .
If it wern't entertaining, I wouldn't keep coming back.------the BigSky