gas mileage question w/ cracked manifold

[Imakrazy]

so when i bought my wrangler i was told that the exhaust mani had a crack in it and its definitly obvious with how loud the car is. i was wondering if me replacing that would give my auto 1998 4.0 v6 any better mileage because right now im only getting a horrible 13 to the gallon and thats mostly highway. i would put money into my jeep but if its getting that bad of mileage lifting and putting offroad tires is only going to make it worse..i have the mani order to pick up t quadratec tomorrow regardless because the noise is extremly annoying i was just curious if it will affect my mpgs. thanks for any insight in advance!

 

[JPNinPA]

Fix the exhaust leak and do a tume up clean teh TB and IAC then check your MPG if this is a stock set up you should be 15-16 mpg. The exhaust leak will cause O2s to send bad info and change the fuel air ratio.

 

[54cj3b]

wish I got 13mpg What part of your manifold is cracked some can be welded
and if your worried about 13mpg think about maybe if your lucky if you add a lift and tires 8 or 9 mpg that's the price we all pay for owning a jeep , I have 6
1 4 cyl dj5 postal jeep 9mpg,1 6 cyl dj5 postal jeep 7/8mpg,1 6 cyl xj postal jeep 12mpg,1 6 cyl xj 9 mpg,1 6 cyl kj 12mpg,1 v6 cj3b 18mpg

It must be a jeep thing

 

[Imakrazy]

thanks guys and yea if im gonna lift one now il start with a 4cyl yj

 

[volaredon]

the one on my 97 XJ is cracked, it's down a LITTLE from what my 01XJ got but not much. Gonna pop it off and weld it up. just like I did on my TJ about 5 years ago.

 

[superj]

thats what i always did to them, just weld them up. all the xj we had had cracks but my 87 i traded for this 87 yj.

 

[Imakrazy]

finally just did it today. i had someone who has more experience help me. it was cool taking out the intake manifold and everything to get to the exhaust. it feels like a brand new jeep with the new manifold now

 

[volaredon]

did u swap in a Ford motor? I see in your 1st post that you claim to have a 4.0 V-6.... not if it's a JEEP 4.0, it's not!