rx8 idle problems. new rx8 owner.

I have a 2004 rx8 MT with 43,000 miles on it. Takes about 1.5 seconds to start. Sounds like from other threads that's normal? But anyways after the car warms up and im at a stop light or in a parking lot just idling the rpms fluctuate after 25 seconds or so. Its like an engine misfire for a normal engine, runs at about 1k and will dip to like 900 and then back to 1k real quick. I can feel the car shake during the half second it does it. It never goes about 1k or lower than 800. It kinda vibrates the whole time it idles too (nothing real serious but you can see the stick shift vibrating) ive been reading forums for several days but nobody seems to have my problem. Seems like everyone elses is more severe. Ive seen youtube videos where the rpm doesn't move at all so there must be something wrong. I just bought it from a dealership less than a week ago and the dealership is an hour away so I dont wanna drive there and find out my small warranty doesnt cover it. It only seems to do it when the engine is warm and only when im completely stopped. The ac doesnt seem to play a role. I paid about $17,000 for this car after taxes and my outrageous 24% apr. Any help is appreciated. I have new plugs wire and coils in the mail but I have a feeling it wont fix it. Also just put lucus fuel system cleaner in but that was only 5 miles ago so it hasnt even gotten a chance to take effect. Thanks guys!