My girlfriend drives a 02 wj 4wd with the inline 6. What are some actual proven ways to increase gas mileage. She drives long distances for work and it's getting ridiculous with gas mileage. I was thinking a cold air intake for sure but what else

 

I think you'll find the stock intake filter system IS a cold air intake. My WJ has a snout on the airbox that pulls air from in front of the radiator and gives a little "ram" effect at speed. The only REAL way to get better gas mileage is to put lockout hubs on the front axle. The parts are expensive and require special hubs and half-shafts. You could also remove the half-shafts, take apart the CV joints, reinstall the axle stubs, and plug the holes to the diff. Of course it will only be 2WD after that. This will only work with the 242 t/case. If you've got the Quatratrac II, forget it.

A low restriction muffler will only give you a little bit more mileage.

 

I have a 2000 WJ 4.0 I6 and get around 14-15 mpg on short local trips, 22-24 mpg on a decent run.
Short journeys and heavy traffic really knock the mpg down.
What sort of mpg are you getting & what were you expecting to get ?
Few people buy these vehicles for the fuel economy...

 

She's getting about 15 on average. I have a Xj that gets 6 so I know there not mean for mpg but even 1-2 more mpg would be awesome. She got the jeep before she got the commute for work. And she's mostly going county roads with no traffic

 

I did a round trip of about 30 miles today on mainly country roads, no heavy traffic and got 18.4 which I don't think too bad as there were a lot of hills on the route.
Maybe her Jeep could use a tune-up ?

 

My '00 WJ 4.0 with 160K on it gets me 16-18 on the highway, 12 to 14 around the local area, and 10 on my newspaper route. That's using E10 regular gas. You could probably get better mileage using Premium without ethanol, but that wouldn't be cost effective.

The main reason Jeeps don't get better fuel economy is rolling resistance. You have the drag of the front drive components whither they're under power or not. Just make sure your air filter is clean, your tire pressures are up, and you don't have any dragging brakes.

Oh, BTW, you're pulling 4000 lbs with only 190 hp.