ok so i need some suggestions here! ive got the rattleing sound that starts when engine is warm and starts at 1200prm and dies off at about 1700rpm...its not the cam phasers bc i have that and know that sound...this noise is coming from right under the cab...does it in park and when moving...sounds like a heat shield or something but i have been under the truck and bent around the shields that were close to other parts...still rattles!

its hard to explain but just sounds like a metal rattle...i have aftermarket duals with no mufflers but still have stock cats...the exhaust is all solid as a rock! any suggestions would help! thanks in advance guys and gals!!!

 

Check the lifting points on the engine up on top. My buddy has a 4.2L and his were rattling whenever he was at about that rpm range. It took us forever to locate.

 

i think i have the same problem, but i think its cats.. i have custom exhaust too but stock cats

 

i had the same rattling lift points on my 07 v6 too....ill have to check into that....

aidswold-can the cats cause this? maybe something inside the cat?

 

well if one of your cats is done. it will rattle when you rev it.. just get someone to rev it. while u are under listening

 

yea havent had anyone to help me out with that yet...tried reaching in to push pedal while beside truck but didnt work out to well!!

 

Could be a loose baffle in the muffler as well. Try rapping with the wood end of a hammer on the outside of your muffler to see if that's where it's comming from.

 

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That's what happened to my original exhaust. Had a Flowmaster 50 series muffler on and rattled but only under certain times. Finally figured out a weld on a baffle inside the muffler was broken.

A rubber mallet would work too, just nothing metallic.

 

no mufflers on the trucks...4 cats and straight back from there....anything else?