Just had my S3 (2007) MOTd today, and its now behaving strangely on idle.
It is revving automatically to 1.5K - 2K rpm, then lowering back down, and repeating. I'm also hearing a fairly quiet but high pitched sound like a fan belt. When I drive it goes back to normal.
Any ideas on what this could be? I've been assured that nothing in the MOT could have caused anything like this.
Thanks in advance.