Gas Milage question.......

[IamJEEP]

Ok, I'm sure this has been covered before but, my searches have not helped. I have a 2006 3.7L and noticed I am only getting an average of 15mpg. Is this correct or could there be something wrong? I usually drive in the city but, sometimes on the highway. I took a trip to Orlando last weekend and averaged 15mpg on the highway. When I drive around town, I read 14.8mpg, what gives?

[Sal-XK]

Well if you have bigger tires and did not correct the speedometer that throw it off.

[IamJEEP]

Nope, stock tires. But, it does have a lift.....

[LWM]

Nope, stock tires. But, it does have a lift.....

The lift will effect the mileage a little but with a 3.7 you should be getting a little better (not much) than that. Other factors do play into the mileage like the terrain, weather and they type of fuel you are using.

[IamJEEP]

The lift will effect the mileage a little but with a 3.7 you should be getting a little better (not much) than that. Other factors do play into the mileage like the terrain, weather and they type of fuel you are using.

UPDATE........

I have found out that, from that other forum, I have made a "NOOB" mistake. I was not aware that I can reset the mpg display, so I've been riding around with older readings. I have since reset it and its reading around 17.5 city.

The terrain is flat land (s. Florida), and I've been using 89 octain middle grade fuel.

Do you know if a CAI and/or exhaust will improve mpg on a 3.7L?

[ScorpionCrawler]

I have a 2006 3.7L and noticed I am only getting an average of 15mpg. Is this correct or could there be something wrong? I usually drive in the city but, sometimes on the

I just completed a trip of 3379 miles.
From NE Ohio to starting point of NYC. Included in our trip was destinations in Connecticut, Rhode Island,New Jersey,Maine, New Hampshire and Vermont.
A larger quantity of my mileage was mountain roads in Maine, New Hampshire and Vermont.
I would guess 1/2 the mileage was 2 lane mountain highways.
I even had 4hrs at 20 mph on rte 95 north of NYC
Included in this was climbing and descending Mount Washington 1st gear for 8 miles.

My average for the trip was 18.9 mpg.
I also have 06, 3.7 and stock tire size , no lift, Iridium plugs (never noticed and increase in milage because of them) Mobil 1, current mileage is 106,730.
On the top was the mopar roof bag carrier, LOADED.
So your mileage seems low to me.
A shorter trip that I checked mileage on was one to Columbus and that was 20.2.
I don't drive with a heavy foot and if speed limit is 65 I usually set the cruise around 72.


When I drive around town, I read 14.8mpg, what gives?

My around town mileage is around 16.9.

Hope this helps,

[LWM]

Do you know if a CAI and/or exhaust will improve mpg on a 3.7L?

Yes they will! But the question is by how much and how long will it take you to recover the expense.

A CAI will give you more air intake and the exhause will move it out quicker, this effect is known to increase the mileage. The problem is that you will only pick up maybe 1 MPG if you are lucky and it will cost you an estimated $400 give or take to gain that 1 MPG. I will leave it too the math majors to determine how many miles it would take to recover the expense.

[IamJEEP]

O.k., now I'm really confused.........After I had reset my average mpg I was reading 17mpg city, I was stoked. But, lately I've been reading from 12mpg-13.5mpg, wtf? I havn't done anything different, same gas, same style of driving, no long trips, average of 60mph..........................What gives?

[strokeZ]

What was the ambient temperature? I have found that the 4.7L really becomes inefficient somewhere around 90 deg F. Below that temp I can usually get 17 to 18 on the highway (flat few hills) but above that it drops to between 14 and 15 mpg. I live in the Houston area so its also quite humid, which does not help.

[IamJEEP]

What was the ambient temperature? I have found that the 4.7L really becomes inefficient somewhere around 90 deg F. Below that temp I can usually get 17 to 18 on the highway (flat few hills) but above that it drops to between 14 and 15 mpg. I live in the Houston area so its also quite humid, which does not help.

It's been 85 to 95 degrees here, feels like 100 with the humidity.

Yesterday I took a 20 mile drive at 60mph and averaged 23mpg. When I got into town, stop and go trafic, I was averaging 16-18mpg. Same gas 87 octane, 35psi in the tires as recommended by door sticker, 89 deg outside, Ño wind and flat land.

Is there a "proper" way to reset your mpg reading? Should I do it while driving or before I start to drive?

[LWM]

Is there a "proper" way to reset your mpg reading? Should I do it while driving or before I start to drive?

Both of these will have the same effect, if you reset before you start driving you will have that 1 mile where you used more fuel to get up to speed but the rest will quickly adjust to make up for that little bit of extra fuel. I say just push the button, you will get the most acurate at the moment reading possible.

[Doc in AZ]

my wife drives a nissan and the computer gives an instant fuel economy as well as a long term.

while displaying in the instant mode when you floor it the reading is single digits, when you let off and coast it goes up to 60mpg.

if you display the long term it will give you the average since the last reset. the longer you drive between resetting it the more accurate "average" you will get. if you reset it every 10 minutes you can maniuplate and MPG you want.

[IamJEEP]

my wife drives a nissan and the computer gives an instant fuel economy as well as a long term.

while displaying in the instant mode when you floor it the reading is single digits, when you let off and coast it goes up to 60mpg.

if you display the long term it will give you the average since the last reset. the longer you drive between resetting it the more accurate "average" you will get. if you reset it every 10 minutes you can maniuplate and MPG you want.



I usually reset between fill-ups.

I've been getting 22mpg highway and 12mpg city. Is it supposed to be that much of a spread?

[Doc in AZ]

sounds like you are resetting it a lot to know what your city/hwy mileage is.... but to answer your question it all depends on how you drive.

my 06 dodge ram had the same computer your jeep has. i reset between fill ups. i averaged 15mpg with a combination of city/hwy driving. on road trips i averaged closer to 20. my wife driving the same truck averaged about 12 city and 16 hwy.