No offence mate, but it seems to me that a lot of people on here have the same attitude, i.e. common problems like that dont matter, just because its common doesnt mean its ok to leave.
It run fine upto a week ago, there must be some sort of problem, however small. They dont come off the production line like that, therefore to me its a problem I would like to be able to resolve.
But yeah, spark plugs will be the first to replace.