okay... I have a 02 F150 Supercrew that has a K&N Cold air intake on it, ever since it was installed (Aug/2010) I have noticed a strange noise coming from what seems to be the Intake tube. Its like a chirping sound or baffling sound, it can happen at idle it comes and goes, and happens when the truck is down shifting for instance coming to a a stop sign. Colder weather seems to make it happen much more frequently. The truck idles fine, and has NO other issues or problems. I have taken it to an authorized Ford Garage, they claim that there's nothing wrong with the truck and its the K&N system. I've contacted K&N, sent them pictures, they said there's nothing wrong with the setup, and that I should take it to the Ford Mechanic. The Ford mechanic's only recommendation was to go back to stock air intake. I know a TON of people with this system on F150's they do not have any issues. Something has got to be wrong right? Has anyone experienced this problem or have a solution?Thanks for any help as this is a most annoying!!

 

I'm not sure of the sound you are describing, but with any open air filter it's going to make more noise and be louder than the factory intake setup.

 

yes i agree, it would be louder.. but this is a chirping noise that seems to come and go, like its echoing through the intake tube. I wouldn't consider it to be louder, its a sound that comes and goes. Also, like i said, I've seen and talked to (and heard) plenty of other F150's within the year range and it doesn't make this noise. So i don't know.

 

Sell the K&N setup, buy a factory intake set-up from a salvage yard........ and do the $15.00 Gotts Mod

 

Simplest thing to do is put your stock intake back on and see if it goes away. Wouldn't hurt to clean your IAC either. They have been known to make noise. Which would be amplified by your intake. Post the pics up of the setup if you can. Could be something like a pinched tube. Air is constantly flowing through the intake, any obstruction would make a noise. I would still pull the IAC off and clean it though. Make sure it is moving freely. If its hanging up a bit... may be whats making the chirp.

 

I notice the same thing with my AF1. When ever i clean my IAC it goes away for a awhile...

 

okay. The noise has now driven me completely nuts. I have had it too another garage, and they weren't able to find anything to fix. I have completely gone over the CAI system for issues, and haven't found anything. One thing I have noticed is, K&N's instructions have you remove the "air bypass valve" or little black box, with a hose. When I put that hose on, it made the sound 100% worse and it did it all the time. So I contacted K&N and they said to put the bypass valve back on. I did, the sound is now back to idle and on downshifting to a stop. I have cleaned and checked the IAC. Seems okay. Does anyone out there have this issue with a resolution?

 

 

The little black box is a muffler. I have noticed that most of the CIAs have the two hoses going into the metal/ plastic inlet tube. My home made and the Ford factory system have those hoses attached at the rubber connector that attaches the metal/plastic inlet pipe to the throttle body. See in the pic of mine that the two hoses attach to the rubber connector.



I believe that having those hoses attached at the rubber connector eliminates any vibration and reduces the noise.

 

Black box is for the 4.6L's and is called the IAC muffler. You mention the "Black box", but I don't understand what you are saying about it. ?? Your not to clear. Forget about the K&N instructions. Anyway, - the IAC must be cleaned while working the plunger (mechanicals) inside the part, carefully. The Black box or muffler should be added in as it was factory. The box or sufficient substitute needs to be there. There's no where else the sound can be coming from unless you have leaks.

 

I think he must have a 4six set up where the IAC is on top by the TPS. Not sure, he doesn't mention what system.