Cadillac CTS weird grinding/metallic noise under car

2006 CADILLAC CTS
127,000 MILES • 6 CYL • 2WD • AUTOMATIC
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KEVINRW28
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Alright so I have a 2006 Cadillac CTS which has 128,000 miles on it. I've recently bought it from a dealership around 1 week ago and I've been hearing this grinding/metallic/vibrant noise that is coming from under my car. It only happens when the car gets warmed up and if you accelerate after 1750 RPM.You can sometimes hear when put in neutral and park. I've used my neighbors lift that he has to check if it was a heat shield problem but couldn't find any of them that are loose. I'm not sure if it can be something in the catalytic converter, muffler, transmission or even the engine. Oil has been recently changed, but the transmission says its 41% life remaining.
Apr 3, 2014 at 1:04 PM
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KNOWLEDGE IS POWER
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If you can't find a heatshield that's loose, then I definitely say you probably have a catalytic converter that maybe separating. Does the car run okay? If the catalytic converter separates, the car will not run well. I tried to get a shop to put it on a lift for you so that you can look underneath the car properly to tell what making the noise
Apr 3, 2014 at 2:42 PM
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KEVINRW28
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I just went to a friends house who has a lift and found on there was something loose inside the catalytic converter. It seems to run fine though.
Apr 3, 2014 at 3:20 PM
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KNOWLEDGE IS POWER
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If what's loose is inside the catalytic converter and it runs fine then drive it. But be warned, it won't be long before you'll need to replace that catalytic converter
Apr 4, 2014 at 2:49 PM