We have had our new pentastar 3.6 dodge avenger for almost a half year, but we took it on a long trip and I wanted to report the fuel economy that I tested both wa)ys on a trip between Upstate NY and Florida:
-I tested it 3 times each way on fillups (not all 100% to empty, some half tanks, some 3/4 tanks but here it is)
-From Buffalo, NY area to near Pittsburgh PA, most travel with cruise controll on 68-70mph...27.4 mpg (calculated, not trip computer).
-From PA to Virginia, 31.0 mpg.
-From SC to Florida, 32.3mpg (cruise controll on 72-75mph)
On return trip, similiar numbers:
-FL to a fill-up in South Carolina, 32.7mpg (traveling mostly between 70-75)
-From SC to Virginia, 30.9mpg
-From West Virginia to Buffalo area, 28.1.
On the norther fillups, travel we generally a few mph less, yet the mileage was worse. Either because the tire pressures were lower in the colder temps...there was a 'winter' formula gas up north but not down south, or the car actually performs better at higher MPG (but that seems unlikely.)
There were a few segments we made some quick fillups that I didn't calculate.
Total payload of the car (passengers plus some baggage) was about 450 lbs.
Trip computer had similar numbers, but it wasn't 100% accurate (probably about 1mpg off either way)
Other than colder temps, on the days we traveled weather was good the whole trip. A little bit of some slick spots on the way down near Erie PA, and some very light showers in FL, but not much else.
Other than posted speeds above, I was easy on the car. Very few times I gave it the gas to pass and got up faster than posted, so I tried to maintain the 65-70mph range without going much faster (despite being passed like we were standing still some times...particularly in South Carolina on I26 between Charleston and Columbia and on I95 between southern SC all the way through GA and into FL.)