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wishful 01-15-2013 12:54 PM

Hello everyone!

I'm sure this topic is covered, however please excuse me because I'm new! I own a 2003 grand cherokee limited edition. When I first purchased the vehicle I got at least 18 mpg on the highway. I now cant seem to get past 11.9 mpg city/highway. I've changed the plugs, air filter, oil to specification 5w30, pcv valve, and I got .2 more mpg. What am I doing wrong/or not done to improve mpg.

Please help, I love my Jeep!

SnoFire 01-15-2013 05:38 PM

Re: Hello!
Welcome to JeepGarage!! Please post in the WJ section of the forums for this issue.

Scottina06 01-15-2013 05:40 PM

Re: Hello!
WELCOME to the JeepGarage family!!!

Hacksaw 01-16-2013 09:09 PM

Help us help you...what engine ? Any codes?, running smooth ? When did you get it ? What part of the country are you in and finally are those figures from the evic or did you actually do the math...

Think Outside !- No Box Required.

wishful 01-17-2013 04:30 PM

Re: Hello!
Hello, Thanks Hacksaw for the reply. I own a 2003 jeep grand cherokee 4.7 liters, I purchased the vehicle in 2011. It runs quite smooth at this time, although I do believe the wheel bearings may need to be lubed or possibly replaced soon. I have factory spec tires which are all filled to spec. as well. I live in Ohio. There are no codes and these figures do come from the evic. though I have not done the math.

Frango100 01-17-2013 05:54 PM

Re: Hello!
Do you feel a lack of power when passing at highway speeds? I had this before and after changing the fuel filter/pressure regulator the problem was solved.
My mpg was down as well and went back to normal after the change. I didnīt measure the pressure at the rail, but it was probably too low.

Hacksaw 01-17-2013 06:27 PM

So you have already been through one or two winters so that can rule out winter blend fuel. It isn't throwing codes and is running well, you have stock tires and inflated properly, you did the normal maintenance stuff ...I'd listen to Frango he's pretty sharp. I'll ask two more questions did you use oem plugs and if the numbers don't come from the evic and you haven't done the math how do you know you're actually getting 11.9 mpg (please disregard that last thing I'm just feeling snarky) seriously from what I've seen Frango is as good as they come in the WJ diagnoses department (pretty good with a wrench too how many guys do you know that rebuild their own automatic transmissions ?)

Think Outside !- No Box Required.

wishful 01-18-2013 01:08 AM

Re: Hello!
Thankyou both, though I will do as you suggest, I hope its not too difficult, although the companion site does offer step by step instructions. Hacksaw it's mighty big of you to confer this issue to Frango100's expertise, obviously you are pretty sharp yourself, in my judgement. And to answer your questions respectively... I have'nt noticed any lack of power in passing though I seldom have done so. Secondly I did not use OEM sparckplugs, however they are identical to the plugs which were installed before I changed them. In other words the're the same plugs in which I was getting 18 mpg with before the switch. Lastly when I first purchased my jeep, I would notice a steady climb on the evic once I went onto the highway, (say from 14-18 mpg) and of course a decline after exiting. It now stands at 11.9 city/highway. It was 11.7 before all the maintenance, and only only climbed to 11.9 after driving quite some distance on the highway.

wishful 01-19-2013 10:58 PM

Re: Hello!
Issue resolved! I replaced the fuel filter, I now see 20.9 mpg hghway evic after only driving 20 or so miles. It was challenging to remove the filter however after disconnecting the mounting bolts, and two 2 tab quick connect lines I vised the filter to the axle and was able to remove the push tab line. Thanks to you both!

Hacksaw 01-19-2013 11:10 PM

Glad it worked out ...stick around the forum though there is plenty more great info to be had ! I think I'm going to replace my fuel filter and see if I can get over 15.5 mpg

Think Outside !- No Box Required.

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