I know there are similar threads about this but every one just seems a little different then my issue. I have had my 8 for almost a year it's a 2007 A/T with 53k miles, ever since I got it I have noticed a rough idle in reverse and drive. Sitting at red lights is the worst, the roughness is SO unbearable it drives me up the wall. I have changed both new coils and spark plugs. It is Definitely not misfiring at high or low rpm. also it is NOT the right engine mount, I have looked at it and there is no damage at all. Almost certain it is not a clogged catalytic converter, I run the car hard from time to time to get it up in the 6k-red line rpm. Vacuum hoses seems good and snug, it seems that I have done everything I know to solve the issue and it hasn't yet.

other helpful info:
live in south Louisiana (has been a rough idle in both cold and hot weather)
have a drop in high airflow K&N air filter. (had rough idle even with stock air filter)
put on a racing beat cat-back exhaust.

p.s-every now and then it'll idle at red lights smooth as glass, BUT it is RARE! and I mean rare.

Reply's are greatly appreciated thanks #long live rotary!

 

A couple of things that can be easily checked is your ESS and MAF. If dirty, they could have something to do with your idling issue. Clean them and then reset the ECU (20 brake pedal pumps method).