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-   -   My 2012 Summit V8 dropped mileage down to 10mpg? (http://www.jeepgarage.org/f107/my-2012-summit-v8-dropped-mileage-down-to-10mpg-71453.html)

Tom1234 02-08-2014 11:47 PM

My 2012 Summit V8 dropped mileage down to 10mpg?
 
I have a 2012 Summit with the V8 and averaged 12mpg since I did predominately city driving. Highway mileage was 18-20mpg.

Now I have 11k miles and the mileage has dropped to 10mpg. Is this bc of more ethanol in winter gas or should I try a different octane or is it my heavy foot? It seems like applying the slightest throttle now takes it out of Eco.

What could explain the mileage drop and should I bother taking it to the dealer?

JeepGCOverland 02-09-2014 12:01 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
I would take it in. I know that it is a V8, but 10 MPG is just terrible, and 12 MPG isn't too great either. Either something is wrong or you are driving it flat out constantly.

JMP8562 02-09-2014 05:59 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
Q= Did you recently bring your Jeep to the dealer ? do you know if the Flashed your computer for a TSB ?
I was getting the same mileage as you were, I brought mine in for the 50000mi Trans fluid change and they said there was a TSB for the transmission after they did the Flash I went from 18-22 down to 10-13 :eek: I called them and let them know, They said give it time for the computer to Learn the new program installed, Ok I would agree with that thought. After 1500mi had them REflash it and YES No luck but I am still waiting for the computer to learn (3000mi after the 2nd flash) :mad: I am going in to have them install my Rock Rails next week they say 1.5hrs to install them :lol::confused::lol: so they should have Plenty of extra time to figure out why my MPGs dropped after the flash. I am just coming up on the 60000mi spark plug change and I am Sure they will go with that as an excuse :D

JeepGCOverland 02-09-2014 08:56 AM

Quote:

Originally Posted by JMP8562 (Post 972871)
Q= Did you recently bring your Jeep to the dealer ? do you know if the Flashed your computer for a TSB ? I was getting the same mileage as you were, I brought mine in for the 50000mi Trans fluid change and they said there was a TSB for the transmission after they did the Flash I went from 18-22 down to 10-13 :eek: I called them and let them know, They said give it time for the computer to Learn the new program installed, Ok I would agree with that thought. After 1500mi had them REflash it and YES No luck but I am still waiting for the computer to learn (3000mi after the 2nd flash) :mad: I am going in to have them install my Rock Rails next week they say 1.5hrs to install them :lol::confused::lol: so they should have Plenty of extra time to figure out why my MPGs dropped after the flash. I am just coming up on the 60000mi spark plug change and I am Sure they will go with that as an excuse :D

Not sure if you saw my review or not, but tell your dealer good luck with the 1.5 hours. It took my dealer 12 hours, and they charged me $600.

JMP8562 02-09-2014 10:29 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
Yes I have read some write-ups on the rock rail installs and it would take me 1.5hrs to remove the plastic sill guards :D and I have prepaid the rails and labor, told them I will have a family member pick it up and I would like to get it paid in advance They were ok with that :) do I feel Guilty for doing that to them:o NOPE :D:lol::D well a LiL...but I will be the one to pick it up 2 days later just to make sure they did a good job. and I will print a few pages from the forums to give the Poor guy that gets stuck doing it some helpful tips and tricks to get it done Properly.
anyone know a good write up that i can share with them ? I would appreciate the help but he/she would LOVE the help.

MxRacer965 02-09-2014 10:41 AM

I've always done 12 in the city since day 1 with my 2011 Summit hemi. Just par for the course I think.

jgc4ever 02-09-2014 10:58 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
I'm getting 10 mpg too. I drive it like a race car most of the time. I had the TSB flash for improved shifting done. 2012 with 5.7L V8. The gas in our area changed and it's 87 octane with 10% ethanol (and winter blend gas, whatever that is) and is 20 - 30 cents cheaper then before, so I'll live with this. I still seem to fill up about the same number of days though.

mzimand 02-09-2014 12:57 PM

I have a 2014 SRT with 1800 miles and I am at 11.4 mpg . Just about all 1800 mile have come in the city. When on the highway in Eco Mode I seem to get around 20-24mpg but only have been on the highway a few times.

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TurboRush 02-10-2014 08:25 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
... and yes, you'll see a mileage drop with the winter blend as well.

jgc4ever 02-10-2014 08:09 PM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
Now I'm getting 12.1 mpg.

MxRacer965 02-10-2014 08:46 PM

Since I just installed a hemifever tune in mine I started watching close. I babied it today and I'm over 12 with MDS disabled.

kkreit01 02-11-2014 11:49 AM

Re: My 2012 Summit V8 dropped mileage down to 10mpg?
 
In pure city driving -- stop-n-go, or small-town 25 MPH driving, I can easily see the Hemi only getting 10 MPG in winter. I always drop 1-2 MPG in the winter -- on all my vehicles. My Hemi Ram gets in the 12s in the winter, and that's a "mixed" commute of some highway. It's a 4x4 Crew with 3.92 gears, and heavy LT A/T tires in OE size. If I were doing small-town driving, I'd be lucky to get 10 mpg.


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