This is meant with the utmost politeness:
Firstly- not to be a nag, OP, but please don't call a Jeep Wrangler a truck!
[I can’t believe no one has mentioned it in the thread yet. I tried to read it all, so if I missed it please forgive me…]

Anyway...
Well, the first couple years, on my brand new ‘08 4dr unlimited X Jeep everything was so tight that I didn't think I was getting the "true" mpg ability. A couple years into the break in period I noticed the mpg’s went up by maybe 1 mpg.
So I started to get about 16 – 17.5 mpg city, and about 18.5-19.2 highway. Things got better as I began using synthetic oil.
The Wrangler is bone stock except for the aftermarket Cibie headlights, wiring harness, and a drop in K&N air filter.
I was contemplating getting the flashpaq or some other fuel reprogrammer. But I never heard enough consistent praise from the community to justify the expense.
One hot summer my family [note: the two adults are over 240 lbs each] took a camping trip up to the mountains. Uphill for 30 miles, with the Jeep packed FULL of camping gear and three bikes and a heavy bike rack attached--the A/C blasting the whole way.
The mpg computer started to show 16mpg. Then it started to climb. We continued uphill and a few miles more, I glanced down and couldn’t make sense of what I saw.
22.0mpg??? Then it climbed all the way to 24mpg!!!
Very strange!
However since then, my putting around town is back down to 16.5-17.0mpg.
I did not really trust the mpg display, so I’ve tracked the mpg using the ODO and the gallons I put in. Did the math, and found the computer is optimistic by about 2-3mpg.

 

You guys and your metric talk. What's wrong with a good old fashioned mile and a gallon? All this talk of liters and kilometers is making my head hurt! JK, I know we're the odd ball ones compared to the rest of the world, other than the UK with imperial gallons and such. LOL.

 

OMG! I'm so sorry! You know as a non native speaker (German) everybody always nagged me because I called my Landrovers cars. Everybody told me "Man, that's a truck!"
Now you are telling me the Jeep is not a truck... My head is going to explode!

adamk73:
You guys gotta switch to metric It's so much easier to calculate with.

Did you know that NASA crashed a Mars probe in the 90s because they had a conversion error from metric to imperial?

 

lol good old fashion metric.. it came first

 

I'll put a note in the suggestion box, but I don't think anyone will listen to me!

And why would we want to switch, everything by tens, BAH! We like 12's and 16's, and we like our water to freeze at 32, not zero! And boil at 212, not 100!

I don't know why the US ever decided to be different than the rest of the world. Maybe I'll have to go look that up.

 

We didn't make it up. We brought it with us.

 

No problem. It’s just a small thing. In the end its all about motoring – on or offroad!
I had an acquaintance once, who got REALLY bent out of shape when I called his Ford F-150 a truck.
He got red and told me in no uncertain terms that the little F-150 was just a pickup!
A TRUCK was like his 10 ton dump truck!

Well I didn’t want to get into a fight over it, so I just nodded! HAHA!

http://en.wikipedia.org/wiki/Jeep#Or...ame_.22jeep.22
http://en.wikipedia.org/wiki/Truck