[Turbowned]

Originally Posted by serialk11r

That's good to hear.

All cars have it these days, it's to reduce HC emissions. When the engine decelerates quickly I'm guessing there's a bit of "ECU lag" because the sensors aren't picking up on the decreased airflow immediately, and you end up having excess fuel injected which comes out the tailpipe in the form of black smoke or a fireball + black smoke. I think that's the reason some cars have that fireball or puff of smoke come out when they shift gears.

My S4 has zero rev hang, and it actually revs quite freely; surprising for a 3800lb luxury sport saloon. It's the easiest car to rev match, too!