Since I replaced my factory filter with K&N drop-in my MPG dropped about 1 mpg.
I used to get 23~24 mpg but not I get 22~23 MPG.

The reason I went to K&N was not only to save $$$ on long term filter replacement cost but also to see better gas mileage or performance.

I don't feel any loss or gain in power but the lower MPG bothers me.

Any thoughts?

do I have to reset my ECU? or whatelse?

 

Idk, just get a Cold Air Intake and call it a day for you. You'll be glad you got a Cold Air once you do, Trust me Who cares about mpg anyways. Its not like any modding is gona help you get 10 miles more per gallon or whatever so just get a Cold Air. Better Performance and your gona use more gas anyways cuz your gona love the sound. Later.

 

I've already noticed improved mpg with my cai, and the improved performance and sound are def. worth it

 

Yeah, they say you do get improved mpg by a tiny bit from putting in a CAI. Who knows. I dont do precision mpg testing so i'll never know and i dont care. All i know is that my TL is pretty good on gas.

 

Over how many tanks of fuel were the before and after mpg figure calculated? Same weather conditions, same driving conditions, same brand fuel? There are a lot of things that can affect fuel mileage.

 

My gas mileage went down too, here is a tip let the pedal off the floorboards once in a while. Worked great for me. Modding cars is fun but makes you want to go faster therefore worse gas mileage!!

 

my driving habit hasn't changed. I open vtec quite often you know what i mean......

I have been recording MPG every fill up in Excel spread sheet. I do it everytime same thing for all other cars I have.
2 year of ownership the average MPG is now 22.9 MPG. HIghest was 28 MPG. Lowest was 20.3 MPG.

 

the weather maybe..??

 

Was thinking about the K&N filter for my car, then there was a post a while ago about the non-reliabilty of said filters . There was also somethingaboutK&n no backing their warranty.
The odd thing is that when I went shopping at Wal-Mart a couple weeks ago I saw the K&N filters there, looked them over and since they didn't have the one for my car didn't buyone.Across the aisle the had Frams for 10 bucks, bought one, and noticed the change, and the better mileage, and more power.

 

1 mpg difference in fuel economy... not exactly statistically significant is it, esp. w/ all other variables factored in, including the method by which you're calculating fuel economy to begin with?