Carbon Buildup in Automatic RX-8 (2006)
 

Just a new owner with his RX-8 wondering how to get rid of Carbon Buildup in an automatic, getting towards winter doing a lot of gas->brake driving I feel it'll build fairly quick. How often should I clear out the buildup? Thank you !

Extra:
 

Also does the engine need to sit before turning off the car? During start up obviously give a few warm up minutes, just wondering. Thank you !

When the weather allows, floor it when it's safe. An AutoX event is also great, both for you and the car.

You don't need to let the car sit before turning off the car. It was an old rumor that this helps prevent flooding and such, but a healthy RX-8 engine shouldn't flood. If your car floods easily, check your ignition components(coils, wires, and spark plugs), compression and battery.

Also, no need to idle to warm up. Unless you have a carburated car from the 70s, it's not necessary. You only have to wait 10~15 seconds before you start driving. Just be light on the gas and keep the RPM below 4000(which should be easy with an automatic) until the car warms up.

Time...
 

How often should I clean up the carbon buildup in the engine, weekly? Monthly?

Unless you live in the great white north of Canada, don't idle it to warm it up for extended periods of time. The car runs pig rich at cold idle and it's that rich period when carbon forms most quickly. The engine will warm up faster if you drive it, just keep the revs under 4K until it's warmed up.

Even in the coldest Chicago winters, I only let it idle for as long as it takes me to get situated before driving off. This is 1 minute at the most and that's only when I'm being picky about what podcast I want to listen to.

What UnknownJinX says is the conventional wisdom. Get the engine nice and warm and get on the gas hard. The idea is that you want the build-up nice and warm and mobile and you want to put load on the engine with lots of air flowing in and exhaust flowing out at high speed.

I just do it whenever condition allows. Revving a rotary hard is not bad for it at all, just make sure you keep up with your maintenance, mainly the oil level, premix(if you do it), coolant and trans fluid(very important on an AT - the ATF drives pretty much everything in an AT).

I live in BC and we mostly just get rain in winter, very occasionally snow. I just wait for under a half a minute and drive away.