ermmm i feel the same!!! either using performance or not!!! but for VTEC they prefer using iriway 7 and iriway 8 for modified engine!!!!Sorry, too lazy dig from old thread. Whats the differ using normal and performance plugs? What are the best products in our market? For single cam and also twin cam ....
lot of reasons.. sometimes it might be something minor like plug cables.. happened to me once.Is it the "semput" just bcoz of plug not enough support? Coz my car seems semput2 when low idling la