2005 Rubicon Gas Mileage

Your Rubicon has 33" tires and 4.10 gearing, not a great ratio for
that
size tire. Regearing to 4.56 would restore the power caused by that
4.10/33" combination.

Jerry

Jeff Hendron wrote:
> I have a 2003 Wrangler Rubicon with the 5 spd, 33x12.50 tires, and
~10,000
> miles on it. I drove it to Moab from Colorado Springs in March and
I checked
> the mileage on two tanks of gas. They were both a combination of
two lane
> highways, and Interstate 70 driving. The first tank I checked I
got 17.6
> mpg, and 17.8 on the second. I was holding it to 65 mph on the
interstate.
>
> I don't have a problem with the gas mileage as much as the lack of
power. My
> 1991 Wrangler with 4.0L/5sp had a lot more power than my Rubicon! I
wonder if
> anyone has tried a non Rubicon ecm in a Rubicon? And would it be as
easy as
> unplugging the stock one and plugging in a non Rubicon one or do
they interface
> differently?
>
>
> Jeff Hendron 2003 Jeep Wrangler Rubicon
> MatrixOne Support Skyjacker 4" lift, JKS Disconnects
> Agilent Technologies Fabtech Front Bumper, Rock Krusher Rear
Bumper
> Co Springs, Colorado Rock Krusher Rock Rails, Custom Swingout
Tire Carrier
> (719) 531-4319 33x12.50 Goodyear MTR's, Mickey Thompson
Classic Lock Wheels
> Bush Whacker Fender Flares, Warn XD9000i
Winch
>
> Yamaha WR250ZF
>
> Campbell C Freeman > wrote:
> : Hello,
>
> : I have a 2005 Rubicon, which I purchased about 2.5 months ago and
it
> : currently has 1,800 miles. I noticed shortly after driving it for
a few
> : days, that the gas gauge seemed to move to the left rather
quickly. I also
> : seemed to be putting gas in it much more often that my 2001 TJ,
which I used
> : as a trade. I did the "fill-er-up, same place, same pump, same
delivery
> : rate, & cut-off at the pump routine" for a week or two and was
amazed to see
> : an average of 10 mpg. The Rubicon (with California Emissions),
has an EPA
> : Rating of 15/19, whereas my 2001 TJ had a rating of 16/19. I
averaged about
> : 16 mpg with my 2001. Most of my driving is city.
>
> : I did a VIN recall inquiry search on the www.Jeep.com site and
found there
> : was an outstanding Emissions Recall - Reprogram PCM: Notification
Code D46,
> : for this vehicle. The incorrect version of software was initially
&
> : originally programmed into the Powertrain Control Module (PCM),
which "could
> : cause the On-Board Diagnostic (OBD) fuel system monitor to
malfunction." I
> : called my dealer that day and scheduled an appointment to have the
computer
> : reprogrammed. Interestingly enough, that same day I received the
exact same
> : recall notice from DaimlerChrysler in the US Mail.
>
> : I took the Rubicon in the next day...reprogramming took about an
hour, and
> : off I went. I took a trip out-of-town over the weekend, did some
highway
> : driving, and averaged about 17 mpg on 2 tanks of fuel. Three days
later I
> : was driving along in town when the Engine Light came on, began
flashing, and
> : the motor was running on 5/6 cylinders; skipping horribly. I
pulled in to
> : where I was going and called D/C 24 Hour Roadside Assistance. A
tow truck
> : was there in under 20 minutes, and off 'she' went to the dealer.
Next day
> : I was there when they opened, and stayed to find out what was the
matter.
> : The technician told me the computer code said "running lean." He
found gas
> : all over the # 6 spark plug and it was fouled. He replaced it but
it still
> : ran rough. Next he replaced the injector for that cylinder and
that took
> : care of the problem. Off I go, and 'she' is running just fine,
but I am
> : still getting 9-10 mpg in the city. This is the 4.0 L I6 w/ a 6
speed
> : manual (the 'new' German transmission), and a 4.11 gear ratio. It
is a
> : "stock" Rubicon with everything but the hardtop. To me it runs
fine with
> : the exception of this gross gas mileage. Something has to be
wrong.
>
> : Even though I do 95% of my driving in the city, I seldom get above
2 grand
> : in either 4th or 5th gear. I am not a "lead-foot." In fact, I
"baby the
> : thing" since it is so new. You are in 4th gear at 40 mph with
this
> : transmission and rear end. So I usually don't go over 40 in the
city, only
> : occasionally getting to 5th on some longer stretches and of
course, 6th on
> : the highway.
>
> : What could be causing such terrible gas mileage? I understand
that new
> : motors use a little more fuel during break-in, but this is half of
the
> : rating (which I realize is not real-world). I am not running the
AC at this
> : point in the year yet either.
>
> : Any explanations, suggestions, and/or "fixes" would be greatly
appreciated.
> : I will also call the dealership and report the extremely poor
mileage.
>
> : Thanks very much,
>
> : Campbell Freeman
> : South Carolina
>
>
>
--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/


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