I have a 2005 5.4 that has developed a rattling noice while driving.I got under the truck with a rubber mallet and tried to find the rattle.All I could come up with was when I hit the exhaust next to the cat's there is a rattling noice coming from the cat. Could somthing be lose inside the cat. ?

Your thoughts .?

Thanks.

 

Could be a cat brick. It's usually the cat shields. Wrap a 7 or 8" band clamp around the converter you think is noisy. If it's the shield, the noise should quit for awhile after doing so.

Here's a diagram sent out with a TSB covering many Ford models in the past.

Diag #1 -



Diag #2 -

 

Thanks jbrew.

I was wonder if it could be the heat shield. I'll try the hose clamps. What if I removed the heat shield.? Good idea,bad idea.?

Thanks again.

 

It's not a good idea of course and I don't recommend it. I didn't have much of a choice. No repercussions for this instance. It wasn't to long after that, a new system was installed.

To remove, -you cut the tack welds.