No offence taken. Yes i am sure its not the tune. It only happens when you start to tune the engine for power. It starts to do it from about 105 deg C and it doesnt matter what you do with the bottom needle. I have sealed the base of the carby, the back plate and as advised by another Sirio user sealed the slide boot around the carby base. This problem is with my Evo 3 not the STI the STI has not been started.