do a search on the forum regarding misfires. You'll find a lot of info. Do you know if the dealer changed plugs/coils/wires?
Even though it's probably misfire, you should have the code read at autozone for free. Without the actual code, it's all guess work
GBNF --'86 RX7 GX RIP | '88 10th AE T-II RIP | '05 RX8 Ti Grey SOLD--
'07 RX8 GT Phantom Blue Mica
Mazdaspeed || BHR || Enkei/ Falken || AFE/VooDoo || Cobb || Lo-Tek/Prosport || Tein || Racing Beat || KEI || Buddy Club|| XCarLink || Redline/ Lucas