I have a '07 F150 with a 5.4L V8 Triton engine, I was thinking about getting an K&N air filter. Does the air filter actually help gas mileage or make it sound better?

 

May help with sound, but you'll sacrifice filtration efficiency. MPG gains are virtually none. The stock filter does well at filtering and flows more than enough CFMs for the motor.

 

In my experience it has helped my MPG's by about .5 to one. It also sounds a lot better and I do believe it helps in the high RPM's with air flow. I would also suggest not getting a K&N filter because the are oiled. I had one for about 6 months and changed to a AFE Pro Dry S filter. Both are reusable. The oiled filter by K&N is known to foul your mass air flow sensor.

 

If you don't mind Check Engine Lights caused by screwed up MAF sensors that have gone bad because of oil contamination, go ahead and put an aftermarket filter in.

A clean Motorcraft or Wix filter will give you more than enough air and with the proper filtration to feed the engine.

When has anyone ever heard of the stock filter/airbox not allowing enough air into the motor?

 

I put in a K&N knock off not long after I bought my truck because the air filter was shot and the ebay special was $18 and reusable and the Fram one was $11 at Walmart so to me it was worth the few extra bucks because I wont need to replace it.

I doubt it affected gas mileage much. Its been on the truck for 50k and hasnt caused a bit of trouble.

Since Ive got a K&N on my atv I already had the cleaning/oiling kit. Now it looks like a K&N too (it was blue but the oil made it purple).

 

^+1

I haven't had any issues with mine, but I always clean my MAFS a couple days after installing or reoiling.

 

I've had a K & N air filter in my 06 since new and no problems. Yes, it does sound a bit meaner, and I also feel it has helped my gas mileage about 0.5mpg and a little more power. I use my truck to tow my travel trailer 95% of the time. In reading the K & N webiste, it appears most of the problems with MAF sensors is people putting too much oil back on the filter after cleaning it. Mine requires less than 3 ounces of oil. I'd try it and just follow the cleaning instructions and you should be OK.

 

The MAF issue is a myth! User error with oiling will happen to any oiled filter, K&N is the most popular brand hence the rep that it's their fault. Follow the directions and you'll never have a problem with an aftermarket drop-in. Honestly, find a good deal and go with it. You really can't go wrong...IMO a drop-in filter gains are only the fact you never need to buy another disposable.

 

I'm another one with a K&N with no problems. I've had mine for probably 75,000 miles and have never had an issue with my MAFS. I've never noticed any differences in mileage or sound, just the fact that I don't have to buy another filter. Again, just don't go crazy with the oil and you'll be fine.