what ecm programmer would you buy? i have a 96 cherokee.
thinking of reprogramming me the ecm..to improve gas mileage..

here's way......
i had a dead battery last summer. took the battery too get tested. found out it had a dead cell. put new battery in a week later. every since the gas mileage has gone downhill.. i could go 250 miles on 3/8 tank, now its 3/4 for same mileage.

i have drove it about 3000 miles since..

 

From what i've heard, their performance gains are only marginal and the price for power gains isnt worth it. The 4.0 is already as effiecent as it can get.

 

3/8 of a 20 gallon tank= 7.5 gallons of gas. Going 250 miles with only 7.5 gallons of gas gets you 33 mpg.

There is no way you were getting 33 mpg out of the Cherokee. Mine is completely stock. The best I can do is about 20 mpg, which is highway. Average is about 17-18 mpg. You will never get the same mileage as an economy car in your Jeep.

 

haha good point. i barely get 250 miles on a full tank. if anything changed when your battery died, it was the fuel gauge calibration? i dont know, trying to come up with ideas, because theres no way changing a battery out got you worse mileage, chances are something else happened near the same time, it was just coincidence.