In 2001 I bought a new 2001 F-150 reg cab with the 4.2L and auto trans. One of the first things I did was purchase a K&N filter. I had the filter up until recently (43000 MI) when I noticed that the seal around the base of the filter had seperated from the filter. I removed the K&N and put the original paper filter in that I had saved. While running the K&N, I would ave 15-16 MPG. Since putting the paper filter back in the MPG is 19-20. I don't know what would cause this increase, but with gas prices the way they are I think the K&N is going in the trash.

 

that is pretty weird my brother because last time I checked the K&N is supposed to help. lol! Possibly buy a new filter if you feel like(k&n), slap it in and see if that makes a new difference. And yea, I would probably switch back after that if it hasn't made any differences.

-homer

 

Well obviously if you have a K&N filter in your truck for 43000 miles and don't clean it out, your mileage will suck. You could put any new filter back in after you took that old thing out and get better mileage...it all has to do with how well you take care of the filter. Plus, I would have to see it to believe it. getting 4 more MPG's because you switched a filter...that K&N must have been pretty friggin' dirty. But hey, more power to ya if that really did happen.

 

Cleaned the K&N at 25000 mi the first time and was inspecting it again at 43000 mi when I noticed that the foam seal was falling off. I replaced the K&N with the factory paper element and noticed the MPG increase. Another tank has ran through and still have the increase in milage.

 

this just doesn't sound possible man. youre truck probably got messed up from that, u definetly should change filters about every 12,000. MAybe the person before you though that the KN was an air intake(most likely retarded) and slapped that in and left it for like 5 years because u only have to wash the kn cold air intakes about every 30-50K. Which is quite a difference.....this is unexplainable my pal. any other words joe?

-home

 

uhh homer, he has only had the truck since '01, and he put the filter in. all of this has taken place under his ownership. havnt seen ya online in a while???

BSHORT - who knows what happened, but it sounds great, maybe the K&N filter that i have is causing my bad mileage...probably my driving style though anyways, thats awsome man

 

Yea i kinda figured that he bought it new or w/e but i was just making up my own little scenario haha. Neways i havent been on since friday morningor so because i got my new exhaust system friday and its awesome, so i was with my friends driving around all weekend nd hangin out. we wentto a sweet car show also, IF I COULD GET MY FRIGGIN scanner to WORK I WOULD HAVE a few new GOOD pictures in my gallery!!!!! youve gotta seemy exhaust, its different

 

If it really happened, like I said, more power to ya. More mileage is great these days however you get it.

 

Ya gotta clean the K&Ns, and re oil them. Too much oil will decrease air flow, and might mess up your MAF sensor. Note that cleaning does not mean a blast of compressed air, or a dunk in gasoline. K&N is pretty specfic about cleaning.
We race motorcycles, at the track, one out of about every 100 machines use something other than K&N. And most of those have K&Ns by the next race.
Mike