my truck is making a deep metallic clunk sound coming from underneath. i got under it with a screw driver to see if i could hear what the problem was. i heard nothing from the oil pan, block or valve cover but lots of noise from the pass side header, cat and pipe after the cat to the factory cat back. i got no noise from the drivers side exhaust. any ideas? do the factory cats go bad in these trucks? i would hope that if i heard nothing from the block or oil pan it means my bottom end is okay. my mods are tr220 w/112lsa + valve train upgrades for cam, asm long tubes, k&n cold air, and dyno tune. i still have stock exhaust from the headers back. also no burned plug wires or loose spark plugs. truck has good oil pressure right off of start up and no metal shavings in oil. i could not see the header or cat touching anything external to cause the noise so i assume its internal. thanks in advance.

 

All the time or under acceleration? Could be the cats coming apart.

Heres what mine sounded like:

 

thats it. sounds like what i'm hearing out of mine. looks like its time for an off-road y pipe. it does it at idle and under low speed accleleration but goes away (mostly) if i get on it

 

great video

 

Youre blowing ceramic crap out of the cat and its bouncing around in the cat housing and in the exhaust pipe. Get a Y pipe like you said and while you have it apart blow some air through the system and blow the crap out your exhaust tip.

 

Oh yea, try to get it done sooner than later. If a big enough part breaks loose and lodges in the wrong way it will block the exhaust and would make the truck drive like crap or not run at all.

It goes away at WOT because the loose parts are pinned against the wall because of the exhaust pressure. Mine actually stopped for a day or two and then started again. Just depends on how the parts get wedged in there.

 

cool thanks alot for the help. i should have a y pipe by the end of the week, hope it lasts that long.