my spyder 2008 15 000 km revs normaly when starting, but very soon revs decrease and finaly the engine turns on 1 cylinder and stops running. Just replaced spark plugs, but this didn't solve the problem. When engine revs over 3000 rpm , no failiar is noticed. The problem occurs between 1500 and 3000 rpm , no smooth acelerations. Is there anybody who had the same experiences? Any idea what causes that problem and what is the solution?