Gas mileage problem

jdizzle · **Posted:** Fri Dec 23, 2011 11:06 pm

So the last time I drove from Colorado to Nebraska I ran around 20-21 mpg's, which is a little lower than when it was stock (which I expected) but this trip for Christmas I only got 16mpg's. I am just dumbfounded and I can't figure out for the life of me what would cause my mileage to drop that much. Any ideas?

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At The Helm · **Posted:** Sat Dec 24, 2011 12:09 am

What time of year was the 20mpg trip? Winter blend gasoline yeilds worse mileage. If you ran into bad weather this time and used 4wd that would affect it too. If i drive around town and theres a lot of snow here i may only get 11.5-12 mpgs. Summertime it never drops below 16. Check your air filter too.

TitanNine · **Joined:** Sun Oct 16, 2011 10:59 pm **Posts:** 16

Be sure to check your tire pressure. Cold air shrinks, and the pressure may have dropped.

jdizzle · **Posted:** Sat Dec 24, 2011 6:53 pm

I actually just dropped in a k&n filter...the tires all around are at 30psi...

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Mike08Liberty · **Posted:** Sun Dec 25, 2011 11:33 am

Different traffic patterns, different road condition (uphill travel, rough roads), different tread life on the tires, different amount of fuel, different weight in the truck ... take your pick on what can affect mpg.

gren71 · **Posted:** Tue Dec 27, 2011 8:29 am

Not sure who, but some one on this forum spelled it out for me a while back.

A brick is a brick no matter what you do to it! :JEEPIN:

hrogi · **Posted:** Wed Dec 28, 2011 4:47 pm

THe Air Filter might be your issue...

I loose 2-3 MPG between Summer and Winter blanded fuels....
So I was getting 19.8mpg average on my trip this week.

When we did the same trip over the summer we got 22.3 mpg average

Return the K&N and go back to stock...

racer1 · **Posted:** Wed Dec 28, 2011 11:19 pm

Well take it out of 4wd, that will save you about 1/2 mpg. Pump up your tires! Only a pound or so and your tpm will be going off. The sticker on the door says 33psi.

jon153 · **Posted:** Thu Dec 29, 2011 1:24 am

Not withstanding the effects of tire pressure, load, winter blend gas and driving conditions, I have noticed something with my liberty. In cooler weather the engine never warms up all of the way (based on the dashboard temperature gauge). Does a colder engine reduce gas mileage? One of my distant relatives was an engineer who told me that in very cold winters (in both Europe and the Northeastern US), he would put a piece of cardboard behind the grill and in front of the radiator in his car to reduce air flow through the radiator, and thus allow the engine to run hotter. He said this was a quick fix alternative to installing a winter thermostat every year when it got cold. Has anybody else heard of this? He said that is also the basis for the grill covers you see in the winter on big rig trucks.
Also, what is the basis for ditching the K&N air filter? My girlfriend's dad who is a master mechanic up in Michigan told me the drop-in filters were okay but to not waste my money on a cold air ram. His theory was that if something aftermarket changes the air flow over the O2 sensor in the intake even a little bit then fuel economy would be affected, and not always in a good way. Since the tubing has different bends than the stock intake then this can be real problem in some of the CAI's but not in others. Any feedback on this would be appreciated.

tools113 · **Posted:** Thu Dec 29, 2011 2:11 pm

DEPENDING ON TIRES - THEY SHOULD BE BETWEEN 33 AND 35 POUNDS NOT 30

jon153 · **Posted:** Thu Jan 05, 2012 1:58 am

So I've put the paper filter back in and after one tank of gas the mileage has dropped from 16.3 mpg to 15.8 mpg. Not really enough to make a decision on if it makes a difference or not. I am going to try at least one more tank and see what happens. This has been a mix of around town and on the interstate and the driving was reasonably the same for the last two tanks. I haven't really noticed anything else different after swapping them out.

tommudd · **Posted:** Thu Jan 05, 2012 12:58 pm

You can never judge gas mileage on one tank full. Has to be over a period of time, due to many reasons already discussed.
Leave a stock type filter in for several weeks/months. Keep track and then see what its doing.
Also you haven't listed how many miles you have on it or when the last tuneup was.

Diggerfreek · **Posted:** Sat Jan 07, 2012 10:26 pm

I'm with tom as well. My KK will drop 10 to 15 miles per quarter tank when it is close to an oil change.

SETexasLibby · **Posted:** Sun Jan 08, 2012 7:28 pm

Diggerfreek wrote:

I'm with tom as well. My KK will drop 10 to 15 miles per quarter tank when it is close to an oil change.

Mine does that as well (Not nearly as high of a loss, But enough to notice) and that is how I know I'm going to need an oil change soon.

JEEPIN36COKK · **Posted:** Mon Jan 09, 2012 9:02 pm

Maybe it was windy? Head wind? (brick theory) Tire air pressure will help, octane of gas, 85/86 garbage IMO, I stick with 87, 89 when I get down to sea level (AZ). Maybe you had a big breakfast that day, windows down, Sunroof?, need to change diff,tranny, trans, radiator, oil (already mentioned). Could be all, could be nothing mentioned here. Maybe time for Jet chip. I'd like one of those, especially at 5600-5700 feet above sea level.

glsec507 · **Joined:** Mon Jul 18, 2011 4:12 pm **Posts:** 59

can somebody shed light on that whole blocking some air flow into the grille to keep temps higher thingy???? good bad deadly funny????

Gas mileage problem

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