Hi, im marcus. Purchurched my 1998 ZX6R few months ago now and its always been a little rough on low revs but is slowly getting worse. Please note it only does the following on cold engine and low revs up until 4000rpm. It runs sweet as a nut when at normal runnin temp ( 3 bars on the temp gauge ) not sure if its a misfire but when you pull away its very rough almost like a tractor and struggling to pull away at all. Until it hits +4000rpm then she flys? Any ideas aPreciated.