Hi Everyone,

I have a 2006 F150 FX4 Screw with 5.4.

I have searched the forums and have narrowed down my rattle to either heat shield, bad cat(s), or the detonation problem. I get a distinct rattling sound at a very specific high RPM (haven't noticed exactly what RPM that is yet) if i ease up it stops and if i give it more it stops. I don't think it is the detonation since it doesn't sound like a diesel and it isn't likely the phasers due to being a 2006. A week ago i got a CEL with the code p0430 which is cat below threshold on bank 2. I have a feeling that these two are related and it is a bad cat. I found a video with the exact same sound (the sound starts at 00:30):


they seem to think it was the cat as well. as anyone had this same sound and can confirm the exact cause?

thanks!

 

I have had a rattle ever since I changed my plugs. I think mine is detonation. My truck runs great other than the rattle when under a load or going up hill.

 

does it sound like the noise in the video?

 

Hard to say. I had a missfire for a while may have burned out the cat.

 

Someone has to have had this sound happen on their f150 any advice or suggestions?

 

Sounds like bad cat the precious metals are broken and rattling when you get to the perfect frequency.

 

Bump, my dads 2006 super crew has the exact same rattle!

 

It's probably a rattling cat... I would try to find which one it is or just wait some time and drive it, because cat rattles always get worse. Once you figure out what side is rattling you need to figure out why it happened. Cats usually only fail when a rich condition is present or because they are just really really worn and or plugged (high miles on crap gas).. If you had any misfires or drive ability issues on the side the busted cat is on, then you need to fix that or else you will just melt down another good cat. This will probably be a stuck or leaking injector, a bad COP, or a bad plug.
If just your rear cat is rattling then you may be able to just cut it off and straight pipe it.
I had a misfire melt down my rear cat and not my front so I had them both sliced off, straight piped, then got a new exhaust system custom bent for me while I was at it.
Good luck!

 

My truck has 194,000 kms on it and so i'm hoping thats just the life of the cat. I havent had any CEL's for misfire or injector issues, but i do have the CEL for cat below threshold which would indicate it isn't doing its job. With replacing the cats with aftermarket or high-flow cats will i be throwing codes and CEL because they are not OEM? i'm positive i would get CEL if i just straight piped or cleared out my cat. Without using a o2 sensor mod like gotts or a simulator.

 

If you have an 04 or 05 you should definitely be able to delete the rear cats. If its a later model you will need to weld a bung into the straight pipe. This would apply to you if your cat has an O2 sensor in it.

Yes some of the cheaper aftermarket cats will throw codes due to catalyst inefficiency... I've experienced this problem with the brand Walker on my girlfriends old Honda.

In the photos it's hard to see but I have an O2 before and after my only cat on both sides in the factory oriented position.