Ok have been reading the posts from daniel,alex and dallas and i also run sirio engines..... and have had few issues but at moment the 3 engines i have are faultless.... in regards to the engine not comingb back to idle i agree with kickass and use the sirio plug 7 as i was using os 6 plugs and engine was sometimes struggling to come back to idle ,wen i changed over to sirio 7 plug my engines are running at a lower idle cooler engine temp and wow pretty awesome power......