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2005 Rubicon Gas Mileage

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