Brandon Walbeck

I have a 99 trans am WS6 with 86,xxx miles its in really good condition and is rarely driven hard. Original motor and I have a odd exhaust note randomly today after I parked it from driving home. When I started it the exhaust is at idle and there's a weird noise coming from the rear end, it has the stock pipes with a down pipe before the exhaust and the motor is all stock. The exhaust had a noise almost like a knock with the exhaust tone however no noise coming from under the hood or under the front wheels that sounds abnormal. The exhaust knock seemed to go away with rpm after about 1100-1200rpm the car has been idling higher when I went in to neutral until I came to a complete stop for about 30 seconds. I haven't noticed a loss of power and the exhaust note just started today. Could it be the catalytic converter? or maybe it is a engine issue? the check engine light is on at the moment but the code has been my knock sensor and it was just going out it wasn't knocking at the time. Any information about what it could be would be greatly appreciated, thank you in advance.

Mazzenger

iTrader: (5)

Post a video of the sound.