I have owned a puma 1.7 for about 3 months, its always run very well. but last night I was on way to work when it started misfiring, when I stopped it was belching white smoke which smelled very "petroly" got RAC out and he thought head gasket!! said he would follow me home, but as I turned and headed for home the misfiring and smoke disapeared which had the RAC bloke scratching his head?? Any ideas what could have caused this, as today its still running ok!!!