Alright to clarify things I have a 2004 4L V6 4x4. And i used to get about 14mpg in the city and 20mph on the highway. Which I thought was respectable. However I recently put snow tires on ( Bridgestone Blizzaks ) which I checked the mpg amd it stayed very close if not better in some cases. And about a week later I installed a K&N air intake system for the intentions of increasing gas mileage not power. Now with that said I drive conservatively and was certainly expecting better mph..... So I thought..... it went from 14 city to 13!!!! And highway from 20 to 15!!!! Why would a filter completely ruin the fuel economy... Is there something I could of done wrong during installation.... The only thing I can think of is that I didn't disconnect the neg battery terminat allowing the ecu to remap everything. And the only other change to the truck is there is now 4 KC Daylighters on the roof of my truck. Now I know they create drag but could those 4 lights really kill my fuel economy that much???

Please any ideas are helpful!!
Thanks, Anthony

 

Its a 4L its gonna have crap for miliage.

 

dude i get 13 in the city average...you'll get used to it...and i get 18-20 on the highway...its a truck not an economy car

 

I understand that... But I don't understand what made it worse? Ya know it went from good to bad.

 

well cold air intakes do nothing for these trucks...wish i knew that before i bought mine

 

I have 10 lights total in my truck, almost 30" tires, no mods on the engine except for a magnaflow and I never noticed that to much ligth affect the performance of mpg of the engine (2.3L 4Cyl)... you have the big boy of the V6 engines, so this sounds very weird. !

 

The k&n may have gotten oil onto the maf, you should clean it and reset the computer.

 

To clean the MAF can I just spray it with brakekleen and reinstall or will that hurt it? Also there is a whistle at about 2500rpm I know it's the moving air but wonder how to get rid of it :/ very frustrating all of this... I hear ya djflmn

 

There is MAF cleaner, brake cleaner maybe to harsh for the element or not dry residue free.

 

the whistle noise is normal.

 

Like mentioned, 4.0L. Plus winter gas really drops it.

 

What is everybody talking about winter and gas mileage being low wouldn't the cold air make it burn cleaner and more efficient. Or is it the type of gas I'm putting in the truck like E 85 or regular or non-ethanol??

 

dont run e85. the 4.0 isnt mean to run on it.

Usually, they put more ethanol in the fuel in the winter. That, plus being colder out will make the truck get worse gas milage. I see about a 3mpg drop from summer to winter. Also, I warm up my truck in the winter so that also takes a toll on the milage.

 

^^^^^
This. I normally get 17-18 city and right now I am averaging 15.5

 

Colder air = more fuel.

A CAI pulls air from the stock location it does nothing for air temps it just gives you a larger filter and a shiny tube.

Also winter blend of fuel doesn't burn as well as the summer stuff so you will see a slight mileage hit there too.