I've go a 99 xj 4.0 I6 4.5" lift with 31x10.5 All terrains. I get about 14mpg is that pretty low? I hear some people get about 18 with my set up. If so what could be my problem? I'm thinking maybe bad O2 sensors, I'm at 145000 and I don't believe they've been changed, and my engine putters a little bit at idle but runs fine other than that. Any input would be greatly appreciated thanks

-Joe

 

That's lower than some, but other people only get 10-12 mpg. I get 17-19 usually. Most of it is the way people drive; putting the pedal to the metal every time the light turns green will eat up your gas.

Have you given her a thorough cleaning lately? Air filter, throttle body, run some seafoam through the system, pull and clean injectors, etc. If everything is gunked up it isn't running as efficiently. Think about doing the injector swap if you haven't already.

 

Is your speedo/odo accurate? If not, the figures aren't worth much. 14 is not unreasonable.

 

Fuel economy varies greatly due to many factors...

• How you drive
• Where you drive
• How fast you accelerate
• How fast you drive
• Stop and go
• traffic
• hills
• condition of vehicle
• tire pressure
• tire type
• parasitic drag factors
• elevation
• type of fuel you use

Those are just some of the factors. If one person gets an average of 20MPG and another gets an average of 10MPG it doesn't mean the vehicle is to blame. 14 MPG isn't that bad but you will have to either correct the speedometer or calculate in error since you are not using the stock tire.

A 225/75R15 tire diameter is 28.3" you have a 31" tire. This means you will have something like an 8% error. So for example if you go 200 miles on a tank you really went 216 miles. If you used 14 gallons it is the difference between 14.3 MPG and 15.4 MPG.

 

Sigh....

https://www.cherokeeforum.com/f59/be...our-xj-130554/

 

Sigh?

https://www.cherokeeforum.com/f9/how...economy-91879/

Can I just add that as someone that bought a second hand vehicle to "save gas"... I can say that the difference in price I save in fuel is eaten up in maintenance, registration, and insuring that second vehicle.