So a little info about my wj. 4.7 non ho with qt2 and 169000 on original engine, trans, sensors, rotors you name it. Only thing changed was the fuel filter(Napa gold brand) and oil pressure sensor(from dealer it crapped out on me 3 months later) & I carry full size spare 245/70/16. Now I know this to be true as far as parts and maintenance because my mom bought the thing new from the dealer and gave me all the service records when I bought it from her. I get on the highway at 70 mph 19mpg. At 60 I get 21mpg. But I won't get too far into that unless people ask me for more info(BTW hand calculated the evic is always wrong by 1-2 mpgs when I cross reference the numbers). Now in the town I drive in where the speed limit ranges from 30-45mph I get 12mpg at 30mph and 15mpg at 45mph. Now I know a lot will say I'm bs'ing but the only thing I do different than most people(which will be changed once people reply to this) is that I have rebuilt transmissions before and I have always been thought by my father to never drive in overdrive in the city. Two reasons 1 it causes very low rpm which means in necessary fuel usage on the engine(think about driving a manual trans in 5th gear T 45mph) and 2 it puts in necessary wear on the overdrive clutch packs and friction plates. Now I'm from So Cal originally so my mpgs were better as we don't have winter blend fuel. Since I moved to NY the only change I have noticed is during the winter. I get 10mpg city now and 17/18 on the highway(most highways here are set at 55mph so I cruise at 55-60)
Oh and I'm 35 and have been working on cars since I was 14. 1st engine rebuild I ever participated in was on a 70 roadrunner with a 440 6pack swap from a rotted bodied super bird. Just in case members think I'm a 17 year old that doesn't know any better. Hope this opens peoples eyes about leaving the trans in overdrive while driving around town. I mean even my 01 tj with a 32rh came with a user manual that said turn off id while city driving(even though it had no od).