adam1997gipe

I have a 2004 Mustang GT. Whenever I'm driving and the car gets into the higher rpms (4000+), I hear a rattling/pinging/knocking noise similar to the noise created by those plastic hand clapper things. It's very rapid, and it only happens if I am moving. If I'm sitting still and rev the car up, I don't hear anything abnormal. I just recently replaced my spark plugs and coils and changed my oil. The new plugs didn't help, and my oil looked fine. I didn't see anything that shouldn't be there (chunks of metal, milky oil etc...) so this leads me to thinking its coming from the drive train. Has anyone heard this before and could give me an idea on where to start? The noise comes from the front of the car, but I can't tell if it is coming from the left or right side. The car is mostly stock. All I have on it is a cold air intake, off road x-pipe exhaust system (factory exhaust manifold as of now) and a Bama performance tuner. Changing tunes from stock, to 89, 91, and 93 octane does't effect anything either. Any useful input would be greatly appreciated!

jwog666

take a soft hammer and bang on the cat. converters and listen to see if the substrate is rattling around. . sometimes they melt down and break up into chunks, these pieces can rattle around inside the case and make noise, the higher the exhaust flow over them, the more they move around.