Have a bit of a prob with my 2003 lcr did a 15 mile journey so engine was quite warm parked the car on the tuned engine of. Then about 20 secs later Mrs decide she wanted to get out. So started car up the reves shot up to 2000 rpm then when revved it splutters a bit then after about 20 secs went back down to normal idle speed as any one had this problem before and know what it could be.