Changed the plugs approx 3 weeks ago. Ever since the plug swap I have a rough idle and when I turn the wheel, hit the brakes sharply as in a parking lot maybe, and/or drop it into gear from an idle it will stumble hard and eventually die. This only happens with my K&N filter. I thought maybe something had clogged it suddenly so I took it out to clean it and replaced it with my Wix filter while my K&N was drying. The problem completely went away. Re-oil my K&N and reinstall it and the problem is back. It died on me this morning pulling into work while I came to a stop to let someone pull into a spot. Kicked it up into neutral and it fired right back up. I turned the wheel sharp to pull into a spot myself and it died again. I never had this problem before the plug change even though I don't think that has anything to do with the problem but it might, I've been wrong on this thing before. Anyone have anything similar?

2004 F150 NBS 5.4 3-valve, 94k miles

P.S.- Yes it's running on all 8 holes, smooth as silk on all cylinders.

 

Sounds as if you are over oiling the K&N and getting oil on the MAF.

 

x2! how long did you drive with the wix? i'd try driving with it for a little while. especially when the k&n's are more trouble than there worth(for the most part).

 

Is the K&N the same size as the Wix? If it is too small it will choke the engine.

Regards

Jean Marc Chartier

 

It's very possible I've over-oiled the K&N, it's very easy to do. I've had the Wix for a long time but only been driving with the Wix when I've had the K&N down for cleaning. I mainly keep the K&N in it all the time. I cleaned the throttle body today and it helped the problem a lot but it's still there somewhat and I'll probably just keep the Wix in it over the winter. The reason I kinda doubt the over-oiling is because it was doing the same thing before I cleaned the K&N. Sounds like good information though. Keep it coming if anyone has more...

Yes the K&N is nearly identical size to the Wix.

 

I think you have solved the problem. Just use as little oil on the K&N as possible so you don't get it on the MAF. Use a good recommended cleaner for the MAF and you will be good to go.

 

I'm leaving the K&N out for the winter. With the Wix it runs like a champ, better than ever now that I've changed plugs and cleaned throttle body. Thanks for the info guys.

 

If you want a cleanable air filter, get an Amsoil. It's a dry filter guaranteed for 100k. You clean it with a vacuum cleaner or an air hose.

 

From 04 up it is known that some PCM calibrations will cause a lean code if the intake tract is changed from stock.
You may not be able to use the K-N filter. It won't buy any more performamnce.

 

The Wix is a better filter IMO . - Specially when running the stock tune. I ran the K&N for a few years - Never any gains, it was a PITA more than anything.

What I disliked the most; - it didn't matter how much oil I used on the element, the MAF still had traces on the wires.. Oil is a b^tch on those little wires. I had the worry about oiling to lightly just before getting rid of it..

What did it for me is finding residual oil in the intake , just a little bit , but enough to see it if your looking for it. As soon as I seen dust/dirt particles making it's way in the intake and sticking to thje oiled surfaces, I git rid of it - Never again.

She runs great with a mostly stock intake and a Wix. That combo works best for me.

 

I've ran this same filter for approx. 80k miles without problem, I'm chalking it up to my own error of over-oiling it and getting on the MAF sensor. As for the performance gains, I can tell you that I've noticed a significant difference over a stock-type paper filter when pulling my car on a trailer which is right at 5000 pounds. And I have noticed a difference in mileage on long distance trips of about 500 miles. K&N bought me 3 more mpg than the Wix paper filter. Now, were the conditions exactly the same to a "T"? No... This wasn't a controlled experiment but conditions were pretty close I think. My problem is with the excess oil coating the intake and under the throttle body etc... I cleaned the throttle body and underneath it and you wouldn't believe the shade of pink and red I wiped out of it. Now you can tell even when I start it that it runs better than ever.