Hi all im having an issue with my r33 gtst rb25det it has a misfire/backfire when i change gear its doing my head in an im not sure where to go from here if anyone has any suggestions that would be epic. 1993 R33 gtst *new plugs *splitfire coil packs *walbro 450 *fmic *gfb bov *hks mush pod *3" exhaust unsure what it is tbh Thanks in advance everyone.