I've had my 2012 Crewmax with the 5.7L and the 17" TRD wheels with Goodrich A/Ts, for one year (I bought used in May 2013 with 14,000 miles), I drove 21,809 miles. I drive 35 miles round trip to work each day on a combination of rural highway and downtown streets.
Some observations about gas mileage, if anyone else is as neurotic about it as I am:
The trucks automatic avg mpg calculator was never more than .3 mpg different from the actual calculation using the odometer divided by the gas pump gallons meter to two decimal points (323.6 miles/20.38 gallons)
My best gas mileage for a full tank of gas (about 22 gals, when the warning light comes on) was 17.4 mpg. The worst was 11.3 (In the fall when I was doing lots of beach driving). The overall average for the year was 14.9 mpg.
MPG went down by about 2 mpg when the temperature was regularly below 30 degrees.
Keeping all four tires air pressure at 35 ppi, rather than the 33 recommended in the manual, improved fuel efficiency by about .8 mpg. When driving on the beach, lowering air pressure to 20 ppi and then refilling to 35 ppi when back on the road, saved 1.8 mpg over running at 30 ppi at all times.
Driving conservatively: not letting the revs get over 1500 rpm when accelerating, increased avg mpg by 2.
I have a Fold-A-Cover hard bed cover. Open or closed made a less than .2 avg mpg difference. I never tested with tailgate down and bed uncovered, as I've heard some guys claim they do to get better gas mileage.
mw
Some observations about gas mileage, if anyone else is as neurotic about it as I am:
The trucks automatic avg mpg calculator was never more than .3 mpg different from the actual calculation using the odometer divided by the gas pump gallons meter to two decimal points (323.6 miles/20.38 gallons)
My best gas mileage for a full tank of gas (about 22 gals, when the warning light comes on) was 17.4 mpg. The worst was 11.3 (In the fall when I was doing lots of beach driving). The overall average for the year was 14.9 mpg.
MPG went down by about 2 mpg when the temperature was regularly below 30 degrees.
Keeping all four tires air pressure at 35 ppi, rather than the 33 recommended in the manual, improved fuel efficiency by about .8 mpg. When driving on the beach, lowering air pressure to 20 ppi and then refilling to 35 ppi when back on the road, saved 1.8 mpg over running at 30 ppi at all times.
Driving conservatively: not letting the revs get over 1500 rpm when accelerating, increased avg mpg by 2.
I have a Fold-A-Cover hard bed cover. Open or closed made a less than .2 avg mpg difference. I never tested with tailgate down and bed uncovered, as I've heard some guys claim they do to get better gas mileage.
mw