I have a question: does the 4.0 get much worse gas mileage than the 2.5? I have 2 scenraio's stock (both manuals) and lifted (both 5.5 inches) with over sized tires.

 

My 4.0 with Auto,
Stock got 15.5 mpg average
Lifted 5" with 31's it now gets 10.8 Average

 

only gets worse the bigger you go. 6.5 with tall 265s they measure to a 32.8 i get about 9 but i do alot of town driving and empty snowy roads are too fun for me not to waste the gas if you know what i mean lol

 

Actually, in my experience.. 4.0Ls power/fuel wise there is no contest, you gotta floor it more and drive the 2.5L different than the 4.0L. IMO they still need more *****, but cant complain.

 

how does the 2.5L compare fuel mileage wise to the 4.0?
same better worse?

 

This might help what you are looking for....

http://www.fueleconomy.gov/feg/bymake/Jeep1998.shtml

 

im getting 19 MPG with 29 inch tires. i do have a 5 speed though. i do alot of town driving and my highway driving is for the most part stop and go.

that link is cool, but i go through a tank of gas a week, im pretty sure im using wayyy more then that

 

[QUOTE=wheeler;352992]im getting 19 MPG with 29 inch tires. i do have a 5 speed though. i do alot of town driving and my highway driving is for the most part stop and go.

What engine do you have?

 

I can tell you from experience that is complete BS. the way they calculate that stuff isn't real-world. Its in a lab under controlled conditions that nobody will get while actually driving. Your driving habits will affect gas milage more than anything else. I'm sitting on 3" and 31s with a missing driver's side fender and no bumper, I have aerodynamics worse than a brick and I still get a combined 18mpg when I drive it like a fool. If I actually cared about gas milage I'm sure I could squeeze 20 or 21 miles a gallon out of it

 

My 2.5 was about the same as my 4.0. Considering that I was driving the 2.5 around floored usually. They both use the same amount of gas.

 

Fow what it's worth, my 94 with 30x9.50 At's, driven mostly hwy. but with some city, gets 19. I calculate this by dividing miles traveled by gallons put into tank, averaging that over a period of months. It's bone stock otherwise, biggest factor is driving style, I do keep speeds at 70 and below and mostly at 65, but alot of it is just driving the engine in the effecient PRM range of the engine.

 

my wifes 89 4.0 auto gets 20 in town and my 94 4.0 5spd gets 25 hiway and 22 in town. both are stock

 

With the 4 cylinder and the habit of driving lightly I'm confident I get 18+ mpg. Drove from Denver to Fruita (~260 miles) and still had an eighth of the 13 gallon tank left. However, get my Rig on the trail and I think I get 10 mpg. Helps to save the aggressive driving for offroad.

 

It really depends on how you drive, but the 2.5 and the 4.0 aren't going to call that different. For sure, the 4.0 is the motor you want for drivability. We had a 2.5 5-speed, and I could squeeze 25 MPG out of it driving 60 on the highway, but at 70+ it goes down pretty fast. City driving for my 4.0 auto and that car was very similar.

 

[QUOTE=offroad rider;353003]i have a 4.0 HO engine. its a 95 so it has the OBDI computer as well, i havent done anything to modify the engine. i have been thinking about a cold air intake and high flow exhaust though. nothing is going to really help get your gas mileage back when you put bigger tires on besides regearing!