sorry if this question has been asked. Im a competely noob when it comes to rotory engines.
2009 RX-8 6000miles on the clock, 92 gas

on cold starts, the engine sounds like its missfiring for some sort, like small explosions in the exhaust. also I could feel the viberation too.

and the high pitch fan sound after seconds when its started, what is that?

 

Since the car is still relatively new it is still possible to get some backfiring from your exhaust (although ive never seen that happen after 6k miles). The vibration could be your pipes expanding/contracting because its going from cold to hot so very fast...

However, everything i just said could be negated depending on where you live and your current ambient temp.

 

The high pitched sound is your air pump that is used to heat up the exhaust quicker, that's not an issue. As for the rest, It's not a backfire right, but more like a little burp? That's really okay too and you should read the stickies and or do some searching/reading.

 

yea, its like burps. feels like someones kicking my car.

 

welcome to the wonderful world of rotarys.

 

Car is tuned pig rich from the factory ... put put sputter.... zoom Zoom