Zozzers16

Hi I'm buying a Audi A3 sat 04 plate 54000 on clock. Advertised as engine misfiring. Has had new coil pack and plugs. Owner dealer been honest and said could be engine could be electrical?? Maybe something and nothing or maybe an engine rebuild rather Thn new engine as more potential to actually rectify fault. Has anybody any ideas to Wht poss could be Wht potential looking at to Gt sorted? He wanted £1000 bt said Tht he would do for £500.. For me everything fine cosmetically and with rest of car js the elephant in the room with engine misfire??