loss of gas mileage

[davberry]

after the lift 3", on my 97XJ sport, it became very apparent that the gas milage has droped to about 12mpg. after i adjusted the LCA out a bit to give me a 101.4" wheel base the gas mileage got a little better, but not as much as i would like. is it possable to get it up to about 18-20mpg?????
Dave

 

[Rob Bolin]

Well when you lift, it puts more strain on the driveline which the engine has to work a little harder to turn the driveshafts with more angle.. Make sense?

 

[davberry]

sure that does,but there must be some way to make some mods do increase the mpg
dave

 

[verrive]

Aftermarket exhaust, header, and bored throttle body/spacer help from what I hear.

- Kevin

 

[woody]

What size tires are you running? Is the speedo corrected? Going from stock to larger rubber has you driving more miles than the odometer shows...and makes the engine work a bit harder.

The higher presentation of a lifted Jeep's nose/WS won't help MPG , but I can't see it account for a 30% loss in MPG...especially if the tire dia. stayed the same.

What was the MPG before the lift? FWIW my 89 beater +200k 4.0 got 16-18 'country' MPG with +4" lift, 3.55:1, 33" & steel wheels; It stayed about the same with +6", 4.56:1. 18-21 on the highway at "legal" speeds.

 

[Jared]

My mileage dropped from about 18 to 11-12 over the course of a couple weeks. I finally replaced the oxygen sensor and got back up to 18mpg. Maybe yours is bad and it's just a coincidence that the lift happened near the same time. Maybe your tires need more air.

Jaredatriot:

 

[Fergie]

My mileage dropped from about 18 to 11-12 over the course of a couple weeks. I finally replaced the oxygen sensor and got back up to 18mpg. Maybe yours is bad and it's just a coincidence that the lift happened near the same time. Maybe your tires need more air.

Jaredatriot:

I am beginning to think the O2 sensor is my problem too. With 3.55s, 2" lift and 30s I only ever got about 11-12mpg....and now with the same lift and tires, but with 4.10s, I am getting 10-11 mpg.

I have kept up the maint. on it, but have never replaced the O2 sensor.

Is there anytihng else to look at, sensor wise?

Fergie

 

[davberry]

well the tire size and psi are stock, and the o2 sencer is the original, so may be that the 116k that have racked up coul do it?
how much is one?
Dave

 

[davberry]

oh i forgot to mention that the jeep idels rough at low rpms, it will bounce from about 5-600 then jump a little higher, as if its gonna stall a bit but has never stalled on me. could the o2 sencer do that?
Dave

 

[woody]

I dunno much about your HO 4.l, but not long ago while burping the cooling sys, I broke the little plastic hose that connects the throttle body and the MAP sensor (on an 88) and it promted rough/low idle and a approx 50% reduction in MPG

:dunno: 116k would be about time for O2 sensor(s?)

 

[davberry]

how much is a o2 sencer?

 

[SimpleXJ]

You have 2 sensors on that year. One before the cat and one after. Break out your OHM meter and test them both. Across the 2 white sensor wires you should be reading between 5-7 OHMs. If its out of spec, replace. I doubt it's the lift... I have a '96 with 3" lift, heavy front and rear bumpers, and I still get 20 MPG. Might wanna look into your cat. converter as well.

HTH

SimpleXJ