Poor Gas Mileage (2005 4.0 Automatic)

13mpg on the highway for me lol
Only gets worse in the city 😆

EDIT- TO mention i am cammed,ported head/intake ARH Header full 3in. exhaust and i cruise at a minimum of 75-80 MPH all those mods and going full throttle to hear this thing scream to 100+ everyday i get that MPG.....
Driving like a civilized person still cruising at 80 no cutting up in traffic,not going over 100 etc. i'll easily net about 15 mpg....but that gets boring lol
 
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I’ve had 31’s, 33’s and 35’s, autos, manuals, and my mpg is always 11-13mpg. I pretty much only drive in town, so I don’t know about hwy. Don’t expect much. It’s smiles per mile that’s more important.
 
I’ve had 31’s, 33’s and 35’s, autos, manuals, and my mpg is always 11-13mpg. I pretty much only drive in town, so I don’t know about hwy. Don’t expect much. It’s smiles per mile that’s more important.

So sad to hear that. I got 14 mpg city once. I wish I could remember what I did to get it. ;)
p.s. Smiles per gallon is so right. I finally drove mine after weeks of sitting and I finally felt good after working 7 days a week and driving it.
 
I recently purchased a 2005 TJ about two weeks ago with the 4.0 Automatic. I started using it mostly on the highway as I have 2 other vehicles and noticed my tank is emptying quick. I'm going to check the mileage before and after fill ups to determine the approximate gas mileage, but I'm assuming it's going to be poor.

I had noticed a sulfur smell several times driving in which I may investigate the Cat. a lil further, it runs great etc. The TJ has only 95k miles on it currently and it's all stock with no lift and with normal sized tires etc. Just asking around if anyone else notices poor gas mileage on a 4.0 or is it just me. I hope it's not a real gas pig, who woulda thought.


Who woulda thought ???? What were you thinking ??
It's a big, SQUARE box, with a near 90 degree vertical windshield that pushes air, like a snow plow, snow ;)
 
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13mpg on the highway for me lol
Only gets worse in the city 😆

EDIT- TO mention i am cammed,ported head/intake ARH Header full 3in. exhaust and i cruise at a minimum of 75-80 MPH all those mods and going full throttle to hear this thing scream to 100+ everyday i get that MPG.....
Driving like a civilized person still cruising at 80 no cutting up in traffic,not going over 100 etc. i'll easily net about 15 mpg....but that gets boring lol

Do you have any video links for exhaust notes? I’d love to hear the exhaust with that setup.
 
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I drove 96 miles on a full tank, some highway and city, I put in 7.04 gallons to fill it back up. I'm getting 13.7 mpg. It's better than I thought.
 
Do you have any video links for exhaust notes? I’d love to hear the exhaust with that setup.
Will do,Once I recover from this jaw surgery and fix the intake leak I got ill take a video😁
I think I got got some videos on my broken phone,I'll dig around !

Edit- Don't get too excited it's a cammed but it just has a slight bit more duration than stock,and more lift. 250/258 advertised duration,.450" lift for both the intake&exhaust,113 Lsa
 
I drove 96 miles on a full tank, some highway and city, I put in 7.04 gallons to fill it back up. I'm getting 13.7 mpg. It's better than I thought.

Seems within a reasonable range though I'd expect a smidge better on a stock lift and tire size as it appears in your photo. Accuracy on a half tank can be iffy just from the pump shut off variance. I'd expect a little closer to 15mpg.

For context I'm getting 15.5-16mpg now on 33s, 2.5" lift with 4.56 gears and some mild performance mods. I'd been at 13mpg from new with the 33s on my 5 speed Rubicon w/ 4.10 gears.
 
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Seems within a reasonable range though I'd expect a smidge better on a stock lift and tire size as it appears in your photo. Accuracy on a half tank can be iffy just from the pump shut off variance. I'd expect a little closer to 15mpg.

FWIW When the gas pump clicked once during a first fill up, I didn't top it off. I did the same when I refilled it, one click, no topping off. I wanted it to be precise.
 
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I pretty much get 12MPG going up hill... going down hill... in the city... in the country... when it's raining... when it's sunny... in the desert... or in the jungle...

... except one time...

Was on a long trip and for a whole tank I was going down in elevation... I use the Fuelly app to track all my stuff for the TJ... that next fuel up it said I got 17mpg!... I was super excited... but... very next fill up... it was back to 12mpg...

... but it's a tractor motor... I wouldn't expect anything else.
 
Another mileage check, the latest is 14.2 mpg.

That's right at what to expect if your 05 4.0 auto is pretty stock. In fact, 14 was the govt combined rating for that rig when it was new:

https://www.fueleconomy.gov/feg/bymodel/2005_Jeep_Wrangler.shtml

As has been said, a TJ has the aerodynamics of a brick. Also, drivetrain HP loss vs HP rated at the crank is on the order of 30%, dyno proven for mine and others like @Jezza. These vehicles have many worthy attributes, but fuel efficiency is NOT one of them.
 
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