Gas mileage getting worse

Dwphillips

Member
Supporting Member
Lifetime Supporting Member
Joined
Jun 15, 2022
Messages
42
Location
Bellaire, Tx
Are there any settings using the JScan that can increase gas mileage? I have a 2018 JKU with 26,000 miles and it seems to not be getting the 16-18 mpg I was getting a year ago. Now getting 13.5-14.5. Any help would be appreciate.
 

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
3,925
Location
Huntington In
If Texas has some colder air where your located and your letting your Jeep idle to long to warm up wastes gas.
 
  • Like
Reactions: BigAL07

MacGuyver

JK Enthusiast
Supporting Member
Joined
May 13, 2020
Messages
882
Location
Wisconsin
Jscan can't do anything, but have you done anything to make it worse?

Larger tires are going to lower mileage. Check the air filter and make sure it's clean.

Also, how are you measuring the mileage? Are you just believing the computer on the dash, or have you done the math using refills and math. Don't believe the computer.

As stated, colder weather can affect it, along with the weather in general. Wind for example.
 
  • Like
Reactions: BigAL07
OP
D

Dwphillips

Member
Supporting Member
Lifetime Supporting Member
Joined
Jun 15, 2022
Messages
42
Location
Bellaire, Tx
I’ve changed nothing. Wheels, tires, gears, etc
I calculate the old fashion way…
I have used the overdrive on freeway and shorter trips.
I did have a problem with squirrels chewing my Evap hoses and having to repair, splice, or replace some!
 

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
3,925
Location
Huntington In
I’ve changed nothing. Wheels, tires, gears, etc
I calculate the old fashion way…
I have used the overdrive on freeway and shorter trips.
I did have a problem with squirrels chewing my Evap hoses and having to repair, splice, or replace some!

If you only have 26,000 miles on it then it shouldn't need a tune up.

Have you been buying your gas at a different place?
 
  • Like
Reactions: BigAL07
OP
D

Dwphillips

Member
Supporting Member
Lifetime Supporting Member
Joined
Jun 15, 2022
Messages
42
Location
Bellaire, Tx
No changes! Same gas station. I just can’t figure why the gas mileage is lower. Driving conditions have remained the same. On the freeway and on a trip using the overdrive I get 18-20 at 70 mph. But back in town with the stop and go it’s around 13-14 mpg. Does this seem logical?
 

JerryD

¯\_(ツ)_/¯
Supporting Member
Joined
Dec 20, 2019
Messages
690
Location
West Michigan
@BLACKJKU makes a good point. Higher ethanol content will lower mileage. Ethanol has roughly 25% less energy than "pure" gasoline (most pump gas can have up to 10% of ethanol).

But, no nothing in jscan will improve mileage.
 
  • Like
Reactions: BigAL07

JerryD

¯\_(ツ)_/¯
Supporting Member
Joined
Dec 20, 2019
Messages
690
Location
West Michigan
No changes! Same gas station. I just can’t figure why the gas mileage is lower. Driving conditions have remained the same. On the freeway and on a trip using the overdrive I get 18-20 at 70 mph. But back in town with the stop and go it’s around 13-14 mpg. Does this seem logical?
That may be a little low, but city driving is so varied, it's hard for me to compare to you. I would say if your highway mileage is consistent, there isn't anything "wrong" or needs attention. Just the nature of the beast. That mileage is what I get on the best of days.
 

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
3,925
Location
Huntington In
@BLACKJKU makes a good point. Higher ethanol content will lower mileage. Ethanol has roughly 25% less energy than "pure" gasoline (most pump gas can have up to 10% of ethanol).

But, no nothing in jscan will improve mileage.

And also if I remember correctly they started adding more Ethanol in 2022, I know the gas i've been buying doesn't even smell like Gas anymore. I always bought at a BP because it's closer to me and was thinking about trying a Sunoco.

Even my chainsaw I noticed it wouldn't cut as much wood on a tank of fuel like it did last winter.
 
  • Like
Reactions: BigAL07

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
3,925
Location
Huntington In
I just found this disturbing reading.

 

Fargo

Member
Joined
Jan 20, 2021
Messages
50
Location
Fargo, ND
I don't know about Texas, but in ND and other northern states, we get a different mix of gasoline in the winter than we do in the summer. You can always count on lossing a mpg or two in the winter when they change the formulation. When the summer gas starts to flow through the tanks in the spring you see an increase again.
 

Anybodyhome

USN Retired (1973-1993)
Supporting Member
Joined
Jun 15, 2020
Messages
1,172
Location
Nashville, NC
Just making fun here. Who or whom buys a JK, and ponders their fuel consumption. I have wild swings (not the 70s) in fuel rate, depending on the weather unt my idiotic driving Habits. Fun Times
Gotta agree. If gas mileage is in your top 10 concerns when considering a purchase, then perhaps a Jeep should not have been on the list.
 
OP
D

Dwphillips

Member
Supporting Member
Lifetime Supporting Member
Joined
Jun 15, 2022
Messages
42
Location
Bellaire, Tx
My concern is the decrease in mileage. I totally understand jeeps and their not so good miles per gallon. I drove a 1977 CJ7, 304 V8 for 25 years! I know about Jeep mpg.

BFFD053C-7A97-42E9-BD47-7B95DA443E98.jpeg
 

Dirty Dog

JK Enthusiast
Supporting Member
Lifetime Supporting Member
Joined
Sep 18, 2022
Messages
599
Location
Pueblo West, CO
There are really only two major causes for a decrease in mileage.

You're stomping on the loud pedal harder than usual, or the engine isn't running as efficiently. Start with the basics. Adequate air flow in. Adequate fuel supply. Proper AF mixture. Adequate spark. Adequate flow of burned gases out of the cylinders.
 
  • Like
Reactions: JerryD and mrjp