no, would the timing playing up explain the up and down revs? because when warmed up in settles. the problem i have now is the cold start idle, it starts up and stays on normal idle instead of idling at about 1200 rpm. so basically runs like a sack of shit when i start it up in the morning. it has to be something electrical, a sensor as you said before, but i cannot seem to narrow it down. as i said before, it runs spot on once its warned up.