Anybody notice this when they looked at their tailpipes?

The SA said that when its cold the car "shuts down" one side of the exhaust so that the engine will warm up faster.
I never heard that one before - so for the moment I'm giving him the benefit of the doubt.

The car has only been in ATL for a few weeks now, but its definitely not cold here. I personally think its either a clogged muffler or some other restriction. I should be seeing exhaust gas coming out of both tailpipes.

Any advice would be appreciated.

 

Is it happening just when you start the car in the morning or all the time?

check if it does the same thing when you drove it for a while. If it does then something is wrong with your exhaust.

trying to rev it for a bit and see if it does anything. Or get aftermarket exhaust ..

 

Look under the bumper. If it's like my 545 you will see a valve on the right pipe. It is kept closed at idle, but for noise reasons, not warm-up like your advisor mis-quoted you. It opens pretty much immediately after you hit the gas. (mine was squeaky so I heard it plenty of times.)

This picture would tell me you spend a lot of time at idle, and knowing ATL traffic, I'm not surprised.

 

I did look under the bumper and there is some sort of tube connected to a diaphram/valve that sits directly above it. It kinda looks like some sort of EGR valve. Not sure where it goes since it runs around the drv side bumper and I didn't follow it.

I live outside of ATL, so I don't spend too much time in idle traffic. Not much more stop-and-go driving compared to what I drove in Germany.