I know this question has been addressed before but, I have and 03 4.7 4x4 quad cab.It has a 3in body with 35 procomp at's.I put a K/N drop in filter in the truck. but as per the little digital display I have no increase in mpg. I have reset the pcm... no gain. I have been getting around 14mpg with or without the K/N. do I need an exhaust or a whole CAI or stand on my head upsidedown and count to a million??anyone with some imput would be helpful.

 

Did you change your tires the same time as the filter? When I put my new tires on my display went down but my odometer also went off my approx. 10% so i figure I am actually getting 10% better gas mileage than my lieometer. Just a thought.. (But my lieometer never exactly matches my math figures)

 

My digital is normally always dead on... lol.. With those tires, just droping in the K&N there's probably a good chance you won't see much change.

From what I've read on this great forum, the main changes to increase MPG's are:
CAI
Aftermarket Exhaust
and Tuner

I just went with the drop in K&N mainly because I hate the way CAI's look. The tuner is next on my list...

 

The tires were on when iI got the truck.

 

you sure you math skills are up to date? lol....yeah i would think you would be seeing some sort of a slight increase in mileage, but maybe your truck doesnt want better mileage lol...hell mine didn't get better until after i had a tuner....

mine's doin really good on gas now tho...havent had to fill it up in almost 3 weeks...course it hasn't moved in 3 weeks either, but thats not the point lol

 

Increase yes but as you should know that the bigger the tire the "slower" your vehicle thinks your going. So the less miles per a tank (so the computer thinks). But with the 3.55 gears I amnot getting better mileage with the larger tires. So far calculating with my garmin GPS my mileage is pretty close to the same thats driving60% hwy 40% city

 

HP or MPG gains with just the drop in are very minimal. Not to mention that any increase in air flow is being negated by your stock exhaust. To see measurable gains, a CAI and at least Cat-Back Exhaust would be needed. A tuner would kinda tie it all together as well...

 

If you change the tire size, you really ought to correct the speedo with a programmer. It's not just the inconvienence of a wrong MPG displayed, it also means the transmission isn't getting the right vehcile speed info. Yeah, we also know it means your odometer is behind, making it look like the truck has fewer miles as well.

 

i will agree get a tuner adjust the tire size and also you will gain mpg's..... heck that overhead thing cant be acurate... everytime i look at it, its a random number like 5.7 8.4 10.2 bs!

 

a drop in filter is not going to get any change in mileage... think about it, full sized truck that weighs what 5~5500 lbs? with a 245 hp motor at 4000+ rpm's, that gives you a power to weight ratio of 5000/245 = 20.4 lb/hp... add in a drop in filter that may give you 5 hp at 4000 puts you at 250... 5000/250 = 20.00 lbs/hp. what truck ever sees 4000 rpms? anyone who is seeing 4k is not after milege.

if you want a bump in mileage, go get some thermo-tech insulating tape for $20 bux and wrap your fuel rails. you might see a 4~5% bump in mileage. I did this mod along with a fuel cooler and saw a 6.5% change in hiway mileage on my 2000 QC 4x4 with 295's on it.

another change you could do is ditch the 35 pro comps, drop the body lift and put stock tires on it.

sorry if I sound sarcastic but what would you expect from what you have? it's a truck...!