The last few times I got gas, I calculated my MPG, and got 17-19 MPG (all of these were at the same gas station). I have the I6 4.0 and the AW4 transmission. I have not calculated my MPG in a while, and the last time I was getting 12-15 mpg. I did replace a lot of things for example spark plugs, wires, and a thermostat (new thermostat did not fix anything). Is 17-19 mpg something realistic, or did I make a mistake in my calculations?

 

Here are the EPA estimates for the 1992 XJ.

https://fueleconomy.gov/feg/bymodel/...cherokee.shtml. Look for your specific configuration.

Of course, your mileage may vary (this time literally) based on many factors. A good tune, proper functioning sensors and a mild driving style helps. Seasonal changes in fuel blend can affect mileage as well.

Also how you calculate mileage is important. The more tanks you go through, the better. I don't think a "few" is enough.

 

My experience is also 17-19 mpg around town/rural areas...driving habits tend to fluctuate that.. driving like you stole it, trying to be the first one there, or always pulling a hole shot from the stop sign will kill the mpg..On the highway I find at 55 mph I can average right around 21 mpg...at 70 mph it drops to 17 mpg....and with a 2500 lb camper at 55 mph not using overdrive 11 mpg....

 

Sounds reasonable. My 89 MJ gets 15-17 and it's lifted running on 32s. When I first bought it, it had a manual 3.07 gears and 215s and got 21 mpg.

 

@lawsoncl did you regear your speedo? You may be getting better MPG than that. My door sticker has 195/75r15 listed and I’m running 235/75r15 which means the speedometer is off by about 8%. I’m only getting about 13mpg mixing city and highway which seems odd. New plugs, oil, manual tranny fluid. Maybe a new distributor cap and wires will help a bit I don’t know. Seems lower than it should be. Less than 100k on the clock.

 

Yes, I changed the speedo gear and it's accurate. A new O2 sensor would probably help you.