Horrible gas mileage

2k13jk

New member
Im curious ive got a 2013 jk 2dr soft top 6 speed 3.21 gears stock sahara 17 inch rims with the factory 255s on it everything is stick what could possibly be causing me to get 150 miles to a full tank? i always shift under 3k rpms and the gas just dissapears. My old xj when i built the motor with stage 1 parts mated to a 5 speed tranny with 3.55 gears and 35s got better gas mileage im at the point were im going to trade the jeep in or burn it to the ground i have an appointment tomorrow at the dealer ship im going to let them know about this
 

jhires

Member
Im curious ive got a 2013 jk 2dr soft top 6 speed 3.21 gears stock sahara 17 inch rims with the factory 255s on it everything is stick what could possibly be causing me to get 150 miles to a full tank? i always shift under 3k rpms and the gas just dissapears. My old xj when i built the motor with stage 1 parts mated to a 5 speed tranny with 3.55 gears and 35s got better gas mileage im at the point were im going to trade the jeep in or burn it to the ground i have an appointment tomorrow at the dealer ship im going to let them know about this

Purchasing a locking gas cap dramatically increased my gas mileage. Seriously. I was losing a tank a week to someone with a hose and a can.

If that is not the case with you, then you need to take it into the dealer and have them figure out just why your rig is so thirsty. You are either leaking it, something mechanical is wrong, or you are driving it wrong (had to throw the last part in there because I had a GF in my younger days who tried to drive my pickup at freeway speeds in 1st gear)

I get between 16mpg and 19mpg (300+ miles) out of my 2013 JKUR which given the weight and gearing should use a bit more gas than yours per mile.
 

FrankenJeeper

New member
150 to a tank?? I know the 2 door has a smaller tank than the 4 doors bud not enough to make that much difference. I average 350 a tank driving like I stole it. I would think something's up to get that bad of mileage.

Maybe someone more knowledgable in this area will chime in...


2010 JKU Sport
1977 CJ5

Sent from my iPhone using WAYALIFE mobile app
 
I was getting 19 mpg on a stock jkur with bfg km1's and stock 410 and 6 speed man. Now im sitting on a teraflex 2.5bb, km2 35's and 410 gears....are you ready,....24 mpg. ..yes, I said it. I do use royal purple everything, 91 octane and super chips. Maybe its just luck.
 

Tranquillity

New member
Im curious ive got a 2013 jk 2dr soft top 6 speed 3.21 gears stock sahara 17 inch rims with the factory 255s on it everything is stick what could possibly be causing me to get 150 miles to a full tank? i always shift under 3k rpms and the gas just dissapears. My old xj when i built the motor with stage 1 parts mated to a 5 speed tranny with 3.55 gears and 35s got better gas mileage im at the point were im going to trade the jeep in or burn it to the ground i have an appointment tomorrow at the dealer ship im going to let them know about this

A buddy of mine had a drastic change in gas mileage because of a stuck rear brake. Have you noticed any particular smell when getting out of your jeep ? Cheech and Chong stealing your gas is also a viable answer.
 

billybob990

New member
With it being that new my solution more than likely won't be your problem but my xj was getting 13 mpg with stock gears and 31" tires, I took a look one day under it and the return line was rusted so bad it fell apart in my hand when I was replacing it. Now I get 17 mpg, I would take a look at vacuum lines and maybe your return line came off. Just my $.02

I'd rather be fishing...
 

catahoula

Caught the Bug
Tire pressure can make a big difference. I had 225's on my jeep and I believe it stated inflate to 32-35 psi. When I changed to 255's Rubi take off's I kept it at that. Got shitty mileage. Went to a dealer and looked on a 2 door model's door with the same tires equipped and it stated 37 psi. Adjusted and it went up. Went to an express oil change the other day and they checked my tires stating it was set at 43. I told them I had been running them at 37's and wanted that. They insisted someone...me was inflating to 43. I told them they were full of it and it was due heat. IMO. I let them deflate down to 32...for shits and giggles and ran it for a while. I was registering about 14 when before it was around 17-18. I only got around 200-211 in that tank instead of around 280-290. Now I'm back up to 37. I also think the mileage gauge is misleading as well. I don't know about break in period mine has been holding steady other than the change in psi.

Mine is also a 2011 2 dr soft top, 4 speed auto, 3.73 gears with 35,000 on it.
 
Last edited:

2k13jk

New member
Its just weird i took a ride to a truck meet last night 40 miles there and 40 miles back 80 miles total 60 mph steady ac on i used a half a tank im seriously about to trade it in and get rid of this damn thing
 

RockyJk

Active Member
Its just weird i took a ride to a truck meet last night 40 miles there and 40 miles back 80 miles total 60 mph steady ac on i used a half a tank im seriously about to trade it in and get rid of this damn thing

Jeeps ain't for everyone.....good luck!
 

2k13jk

New member
My old xj never gave me problems and i wish i kept it it was a 99 6.5 long arm lift 35s front and rear axle trussed rear disc brake swapped stage 1 built 4.0 5 speed swapped i miss that thing everyday
 

Webe

New member
Your computer could need to be reset/programed. I once had a new vehicle and it had the same issues. I bought a flashpak and reset the chip. It helped some but check engine light came on and due to the previous program my fuel return charcoal filter has bad due to all the fuel being pushed thru it. Replaced that and got excellent mileage.
 

2k13jk

New member
I posted another thread my engine apparently is knocking on the lower end and sounds like a ticking time bomb
 

2k13jk

New member
Welp just went for a drive and checked my odometer i got a whoping 35 miles to a approximately 1/4 tank awesome gas mileage i love it
 

jeeeep

Hooked
I got a whopping 8 mpg on a recent trip, but I had the strongest headwind I'd ever experienced and had to run with OD off just to hold 65mph

but in reading through the thread, you did mention the dealer owner was ready to buy the Jeep back so I'm guessing they'll make it right once you take it in.

I almost traded in my 2010 but am seeing too many issues with the 3.6, not only on this forum but on 3.6 JK owners I know so....it's LS upgrade instead of trade in.

Good luck and hope you get it fixed soon
 

NFRs2000NYC

Caught the Bug
Welp just went for a drive and checked my odometer i got a whoping 35 miles to a approximately 1/4 tank awesome gas mileage i love it

There is something seriously wrong with your rig, so take it in. I have a 2012 JKU with 33s and 3.21s, a bunch or armor, lighting, steel bumpers, winch, etc, and I get about 340 to a tank on highway. When I was stock it was even better. You have a serious issue.
 
Top Bottom