bad economy

octane will not make a difference if its stock, certainly not from 15 to 20. Where you doing the same kind of driving? tire pressure the same?

I had a 96, maybe 97 4.0 4x4 5-speed xj as well. Got about 21 on the highway, 15 to 16 in the city.

Regular gasoline often contains 5 - 15% ethanol which will cause lower MPG as ethanol is less energy dense than gasoline.

>>14838459
so does premium. Unless the fuel says ethanol, it has ethanol.

>>14838506
Depends which gas station you use.
All the major chains around where I live do NOT use ethanol in their premium fuel. It's only in their midgrade and regular.

>>14838506
91 is a popular ethanol free fuel. I've never seen 93 ethanol free

>>14838587
where do you live?

>>14838650
San diego.
Its 4x4, 4.0 5spd.
Daily commute is 20 miles each way, between 55-75mph, 90% highway driving

>>14838344

I was under the impression that 15-20 mpg is ordinary for a cherokee.

is the jeep in the op yours?

if so get that tire off the roof.

96 grand cherokee 4.0 here
I average like 13.6 city, and back when I was doing more interstate travelling I think I peaked at 16
tell me your secrets

>>14838344
Engines with lots of carbon buildup in the chamber will ping with lower octane fuel and run better on higher octane.

My XJ was a glutton for fuel.

Put Premium in it you'll get better fuel econ
>>14841982
>13.6 city,
Lol my V8 gets better milage

>>14838459
Assuming a 15% ethanol blend and rounding the energy density figures (ethanol being 2/3 as energy dense as gasoline), e15 has 95% of the energy density of straight gasoline. If that was the ONLY factor in a mileage discrepancy, you'd be down to 19mpg if you had 20mpg with straight gasoline.

>>14838344
Have you checked your air filter lately?

File: PicsArt_04-14-07.06.06.jpg (1MB, 2882x1818px) Image search: [Google]

1MB, 2882x1818px

>>14838344
>15 mpg

I would kill for 15 for some reason which I cannot figure out I get around 120 miles to the tank or about 8 mpg which is murdering me

>>14842886
Change your air filter, Change your plugs, Be surprised

>>14841982
Something's wrong with your Jeep dude. Ive driven 1 ton vans with a 6.0 v8 that will get 13.5 mpg in the city