Installed K&N lost 5mpg

[knunchakaman]

I have and 95 7.3 f350 crewcab. I checked out my air filter and saw it was badley in need of repalcement. So I went out and bought a fancy one that can be cleaned and regenerated as necessary......I thought my fuel milage would increase but it is noticibly lower....The truck seems to run as well or maybe even a little stronger....but since filter replacement....Im burning a lot more fuel.
Im guessing that now the computer sees more air..its putting in more fuel....my mileage goes down...

I burn straight filtered vegetable oil usually..I get pretty close to the same mileage out of diesel, vegoil or bio...mileage has dropped straight across the board.

Whats the most likely the problem and the best way to diagnose and fix it?.

[planeoldguy]

Sounds like you oiled the filter too heavily, that causes a restriction, you are stepping on it harder, Get ready for a flood of people telling you to throw it away and get a paper filter.

[pipelayerjdh]

Many will tell you not to run K&N because of poor filtering capacity. If you can see the oil bead up on the outside of the K&N, it has too much oil. Try leaving it out in the sun for a few hours. You can try an AEM filter also. AEM has a 4" filter that will replace the K&N and provide better filtration and no need for oil.

[knunchakaman]

I didnt put any oil on it. I think it came ready to put in....i havent cleaned or oiled it yet....it definitely is getting more air that with the dirty old paper filter that was in there...the indicater was pulled way over..with the old filter..

its runs stronger...has more of a top end.......but a lot less mpg..I want to strangle it...especially if it would get me back to 17mpg

[jamstoyz]

i know it seems weird. i put the afe stage 2 and seem to lose mpg's. i may go back to my stock set up.

[IHwelk49]

ditch the K&N and call dale at Tymar performance and order the intake kit or get yourself a filter from him. You can aslo get a 6637 filter from napa. both dale's and napa's filters are paper but flow better and filter the air better than a K&N or AFE

[David '96 993]

These are the insert replacments.

Are people finding mpg improvement with aftermarket intakes? That is what I have been lead to believe and am planning on purchasing one for that very reason.

[metallitera]

I saw a 6MPG drop after I oiled my K&N. It came in the truck, drop in.

I have a 46637(WIX) DIY intake so we'll see how that helped.

[CloverLeafFarm]

diy intake is the way to go

[Tim Langley 1997 f-350]

i actually saw about a 3mpg increase with the afe kit, and 4 mpg with the 3" down pipe 4" to aero turbine and dump but lost it with the chip on the extreme setting i think because i can't seem to keep my foot out of it