I've had this problem for a while, with the 4.8 and the 6.0
There is a rattling/crackling sound heard from my exhaust when under 3/4 to full throttle....only does it when exhaust is cold or until it gets up to temp. Once the exhaust heats up the noise is not there. It sounds like it come from around the cats??? i hate it when it does this,cause it sounds like ****
anyone else have this problem?? My exhaust is gibson shorty headers,dual exhaust(2.5 inch) with x-pipe and Magnaflows dumped before the axle.

 

well, on my dads 6.0 and my truck (4.8),

under 1/2+ throttle i hear a weird *light* crackling rattle type sound every now and then, ... ive been wondering about that for a while now.. i was thinking its bad fuel or somthing..

but on the exhaust side i have ASM LTs, No cats, x-pipe, borlas out the side (lightning style) .. and when i go near cars, or curbs (anywhere the exhaust echos) i hear a tick tick tick type of sound.. very slight noise.. but its there.


so i dunno if i helped or not, but good luck

 

Do you have cats? If so why? They dont check that stuff here. Get rid of the cats a see if it goes away.

 

Yep, still running cats. I'm trying to wait til I can get some Long tubes before I get rid of them though.

 

mine does that too ever since I installed the dynatech long tubes. I suspect I need to crawl under the truck and simply make a couple adjustments...touching a heat shield or something.

 

If it only does it when cold it could just be the dreaded piston slap since it goes away when warm.