I think the standard response to this sort of thing is to run throuh rub-jonny's setup guide, found in the maintinance section, to ensure general setup is ok. Other than that, check the fully closed micro switch and wiring on the throttle body, and checking the intake system fro leaks would be a good idea, in particular the big rubber boot between the air box and throttle body may have splits in it. Best to fully remove it and manipulate the bend to see in about the ribs. There will inevitably be loads of gunk/filth on the inside of the rubber boot and throttle body from the engine breather setup connected to the rocker cover, so while the boot is off, you could clean that up a bit, and check the associated pipes for splits. Simillarly with the ISV, remove and flush out with carb cleaner or similar to freshen it up, checking its pipes too...
