post #1 of Old 01-12-2012, 12:43 PM Thread Starter
neddevine
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2012
Location: Gig Harbor
Posts: 4
Really Bad Gas Mileage!

G'day, new to jeeping, love it except the gas mileage is beyond ridiculous. I know and was expecting bad mpg on a 160,000 mile 1997 2.5L but 8 yes 8 mpg is just wrong. Tires are 30x9.5x15
I am going to change: front and back o2 sensors, injectors, coolant temp sensor, tune up etc. Compression test will also be taken.
There are no codes to review. No vacuum leaks.
Engine runs good, starts right up, has power with no missing.

I need real help please, no I won't sell it!

Any practical input truly appreciated.
Thanks in advance

neddevine is offline  
post #2 of Old 01-12-2012, 12:54 PM
TheBoogieman
Disturbed!
 
TheBoogieman's Avatar
2003 TJ Wrangler 
 
Join Date: Aug 2006
Location: CharlottesHELL
Posts: 32,189
I'd start with plugs,wires,distibutor cap.My 2.5L on 31's had 200,000 miles on it and always got around 15 mpg city.
TheBoogieman is offline  
post #3 of Old 01-12-2012, 01:14 PM
canyon
Registered User
2005 LJ Wrangler 
 
Join Date: Feb 2009
Location: NS, Canada
Posts: 34
It could be a small crack in exhaust header? Just throwing it out there.
canyon is offline  
post #4 of Old 01-12-2012, 01:16 PM
mdm
Farm Wheeler
2000 TJ Wrangler 
 
Join Date: Apr 2005
Location: Elkmont
Posts: 10,050
O2 sensor?

Keep in mind that free advice can frequently be worth less than you pay for it.
mdm is offline  
post #5 of Old 01-12-2012, 01:41 PM
Dextreme
Registered User
1999 TJ Wrangler 
 
Join Date: Oct 2011
Location: Oregon City
Posts: 67
You are talking highway/city mpg correct? Because I get about 8mpg gallon in 4 low.

'99 Chilli Pepper TJ Wrangler -- "Mistress"
Zone 4.25"
33" GY Duratrac's
Dextreme is offline  
post #6 of Old 01-12-2012, 02:29 PM
vtx531
Registered User
2002 TJ Wrangler 
 
Join Date: Dec 2004
Posts: 1,374
How are you calculating this?
vtx531 is offline  
post #7 of Old 01-12-2012, 04:46 PM
4banged
Registered User
2013 JK Wrangler 
 
Join Date: May 2010
Location: connecticut
Posts: 697
Quote:
Originally Posted by Dextreme View Post
You are talking highway/city mpg correct? Because I get about 8mpg gallon in 4 low.
LMAO

Seriously though, I only get about 14mpg in mixed driving with my 03 2.4l 4 speed auto 31" tires. I've done the wires, plugs etc and have considered replacing the O2 sensors so let us know what you find to be the culprit.
4banged is offline  
post #8 of Old 01-12-2012, 04:51 PM
94yjstocklook
Registered User
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: OR
Posts: 299
8mpg definitely sucks. On my 94 4.0 6 cyl. i get roughly 13/15mpg. Sorry for no help but definitely something going on.
94yjstocklook is offline  
post #9 of Old 01-12-2012, 05:26 PM
Jim Shanks
Registered User
 
Jim Shanks's Avatar
2001 TJ Wrangler 
 
Join Date: Jul 2002
Location: Grimes, IA
Posts: 2,711
My last few fills with my 4.0 has netted around 7-8mpg. I'm looking into a diesel powerplant for the TJ.

Jim

"Cracked Cow" '01TonTJ2a, Solid Mfg HP60's, 5.38's, ARB's, PSC full hydro, 14" coilovers, ASD roof and doors, armored everywhere sitting on 40" Iroks.
Owner of IA4x4.com
Subscribe to CRAWL
Jim Shanks is offline  
post #10 of Old 01-12-2012, 06:37 PM
1999TJRED85000
Registered User
 
Join Date: Dec 2011
Posts: 610
I think everyone hit the major things you can check. The first thing I thought was Oxygen sensor. If your sensors are off, the CPU will think things are happening that aren't and bad mileage is usually the immediate result. Plug wires and plugs might hurt a little, but it would have to be running really rough to get that poor of mileage. If you're a mechanical type, give it a full tune up with new wires, OEM plugs, dist. cap, air filter, oil and oil filter change, etc. In other words, do all the cheap stuff that should be done anyway. Oxygen sensors aren't that expensive either, but if you aren't familiar with how they work, take it to a local wrench.

Hope this helps.

F U
1999TJRED85000 is offline  
post #11 of Old 01-12-2012, 06:57 PM
silver97tj
Registered User
 
silver97tj's Avatar
1998 TJ Wrangler 
 
Join Date: Aug 2004
Location: midwest usa
Posts: 626
Hi all lets be honest anything for a jeep tj in the range of 12 -14 mpg is good, anything over 17 is not reality. This is a jeep not a honda civic!.............just do tune up, and change O2 sensor and check cats. etc etc, most of this is do it yourself, pretty easy................

1998 Blue TJ, 4 Cyl., Auto (30rh), Hardtop with installed Sunroof, mostly stock.
31x10.5x15 Mud Tires, TJ Rubicon springs, Mopar Deep Trans Pan and Cooler
Army Vet and proud of it! Have you served your country?
Support our Troops!! Thank You!!!
silver97tj is offline  
post #12 of Old 01-12-2012, 07:04 PM
biffgnar
Moderator
 
biffgnar's Avatar
2006 TJ Wrangler 
 
Join Date: May 2008
Location: Westchester, NY
Posts: 18,684
Quote:
Originally Posted by silver97tj View Post
Hi all lets be honest anything for a jeep tj in the range of 12 -14 mpg is good, anything over 17 is not reality. This is a jeep not a honda civic!.............just do tune up, and change O2 sensor and check cats. etc etc, most of this is do it yourself, pretty easy................
Being honest 14 is not good for me. 14 is a disappointing tank.

Dakar Style Rally Raid in North America: www.sonorarally.com
biffgnar is offline  
post #13 of Old 01-12-2012, 07:26 PM
Dorian772
Registered User
2002 TJ Wrangler 
 
Join Date: Aug 2011
Location: stuart
Posts: 50
Quote:
Originally Posted by Dextreme View Post
You are talking highway/city mpg correct? Because I get about 8mpg gallon in 4 low.
that made me laugh
Dorian772 is offline  
post #14 of Old 01-12-2012, 07:52 PM
catsknr
Registered User
2006 TJ Wrangler 
 
Join Date: Apr 2009
Location: 30 minutes from the Con. Carson City
Posts: 106
Dont forget to check the thermostat, if stuck open it will run too cool and comp. will feed it rich to try to warm up.

/l ,[____],
l-L -OlllllllO-
()_)-()_)-o-)_)
Just Empty Every Pocket
catsknr is offline  
post #15 of Old 01-12-2012, 08:26 PM Thread Starter
neddevine
Registered User
1997 TJ Wrangler 
 
Join Date: Jan 2012
Location: Gig Harbor
Posts: 4
Thanks for all the input.
Filled tank then ran until quarter full then refilled 12 gallons and 97 miles.
Second tank half full 8 gallon 63 miles. Mix of city and hwy driving in 2 wd not 4 low! Thermostat works fine.
Thanks to all for input. I will, over next few days change parts, test and report back.
neddevine is offline  
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Gas mileage seems a bit low bgradisar TJ Wrangler Technical Forum 17 05-10-2011 10:49 PM
Vibration, Bad Mileage, Very Bad Mileage Harley_Jeep_Man TJ Wrangler Technical Forum 10 09-04-2010 06:55 PM
Bad Mileage.. even for a YJ. LoS10 YJ Wrangler Technical Forum 5 01-31-2008 10:12 PM
help with gas mileage baller88 TJ Wrangler Technical Forum 6 03-02-2005 08:05 PM
Gas mileage tj01wrangler TJ Wrangler Technical Forum 21 02-27-2005 03:32 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome