Fuel consumption

Hi guys. I have a Jeep liberty renegade 2004, and the fuel consumption has been pretty bad. So I was wanting to do some upgrades to help with the consumption. Does anyone have any knowledge on wether doing an upgrade - a cold air intake and a free flow exhaust - will improve the fuel consumption? And by how much, will it be worth the upgrade?
Also will old plugs have anything to do with bad fuel consumption…?
Thanks!

What is your current gas mileage? Highway / City?
Are you lifted with larger tires etc? I only get 15mpg hwy with my lifted 04.
Spark plugs should be replaced every 30k miles, with only copper core NGK ZFR6F-11G & set gap at .040 inch
CAI waste of time, and allows more dirt in, stock air box is fine & replace filter as needed.
A free flow exhaust could help a bit.
Are you using a full synthetic 5-W30 engine oil?
Re gearing to 4:10 front & rear is the best bang for the buck.

I’m getting 15mpg highway and 9mpg city.
Got slightly larger tires, 265/70-R16.
Spark plugs have been replaced regularly with correct ones. And yes using fully synthetic 5-W30 oil.
Thanks for this advice about CAI, will have a look at maybe putting a free flow exhaust.
It seems I’m not going to get much more than I’m getting now regard to consumption…

Exhaust or CAI does nothing except make you believe you have more power
On my 04 , 4.5 inches of lift , 265 75 16s, 4.10 gearing , heavy front and rear aftermarket bumpers , skids etc I get 21-22 easy at 75 running down the road
My 03 with 2.5 inches of lift , 265 70 16s and 4.10 gearing gets 22/23 easy on the highway
With that size tire you are running , 4.10 gears are perfect combo, 265 75 16s are too tall and should have 4.56 gears etc
So part of the problem is it is lugging down and not running at the right RPM for mileage

Your mileage is good dude. But thanks for that info. I’ll definitely have to look into my gear ratio then. That could be my problem from what you have said here about yours.

Your mileage is good dude. But thanks for that info. I’ll definitely have to look into my gear ratio then. That could be my problem from what you have said here about yours.

Could ??
OK , carry on then
been regearing for larger tires on various 4x4s for almost 50 years
Keeping the RPMs in the stock range is critical especially on these newer vehicles for not only mileage but power wise as well