1,might be the clutch plate working loose,does it sound like a bunch of cats screaming? 2,immobilizer problems maybe?have you done a search on here for the problem? 3,does your rear washer work?if not then theres is a pipe that runs done the passenger side that has come apart,again do a search.or it might be a leak/blocked pollen filter letting by? hello thanks for your time 1 just a slight knocking no screaming 2 will do a search re immobilizer 3 rear washer doesnt work put it down to the frost but have a good look now thanks alot much appreciated martin