I'd say the majority of your problem is 33s and 3.73s. Somebody with this set up can chime in but most likely it's shifting in and out of overdrive ( assuming you have an auto) when your going at highway speeds to maintain speed. That will kill gas mileage.
not tryna say i think your dumb but are you factoring in the fact that your mileage is off since you havent changed the speedo gear? i did the same thing but now i realized that instead of getting 212 miles to a tank i'm getting about 237-245 meaning i only lost 15-20 miles off a tank of gas. alot better than the 50 plus gallons i thought i lost. my 3 speed setup with 3.73's probably feels the same as yours though. not horrible low end power in 1st gear but it gets weak around 3rd (or 5th gear for you) only way to fix it is re gear... 4.88's for auto's and 4.56 for your 5 speed i believe
Are you using the fill tank, record odometer reading, run down tank, fill tank, record odometer reading and then divide miles driven by gallons needed to fill tank. It seems a lot of drivers estimate the amount of gas utilized by the fuel gauge reading (which is not very accurate). Just a question.
Retired my 94 YJ 4cyl 5spd @ 200K
Now in a 04 TJ 4cyl 5spd CV @120K+
Both as a commuter vehicle in NW, NJ
April 2012.downsized and now a 99er.