I just bought my first Camaro, upgraded from a Dodge dart. I've noticed that it has rough idle when I'm at a stop sign. Tachometer hangs out around 500-600 rpm but it jumps a little. Is this normal for the LS99? I've seen it may be normal in the LS3's. It's still under bumper to bumper warranty, should I take it in? *edit* Happens in warm weather, doesn't get much better after the car warms up.

Car Info: 2015 Camaro 2SS LS99 (auto) w/ 30k miles.

An unrelated issue too, I hear a rattling sound from the exhaust when it shifts. Is this just what the stock exhaust sounds like? Sounds kind of like swirling a marble in a tin can.

Thanks!

 

Don't worry about the idle, if there was a problem, the CEL would be lit. The rattle could be any number of things: heat shield, exhaust pipe out of position, broken baffle in muffler.