HELP!!! Ok when I rev my engine most of the time when it's cold I hear a bad rattling the sounds like its coming from the muffler like the is glass or rocks in it and I can't find anything do anyone know what tho could be

 

Do you have an aftermarket muffler? Sometimes the heat shield will break loose and rattle.

 

No it's stock I haven't down anything to them

 

Also it started happening right before I changed my spark plugs

 

Have you tried getting underneath and looking around for something loose? You can also grab a hold of the pipe or muffler (preferably when it's cool) and shake it around to see if you can replicate the sound.

 

I haven't found anything lose but I'll try to go under a shake it

 

I have this too. Only on a cold start. I've just been really easy on the throttle until I get to operating temperature. Which coincidentally, is good practice anyway. I have the stock exhaust system.
A buddy of mine said he thought it was the cats, no idea though.

 

It's ur muffler bearing.... It needs greasin

 

How do u do that and I hope it's not my cat