Id probabaly go with TPS as first port of call too..
  There was a recall from Yamaha for these. You should also be able to check with Yamaha using the frame/VIN cross referenced with their data base ( ie- they  will look it up )
      They do still go bad, even the new ones. However, I would anticipate that it take use to cause wear, to produce the brass dust that starts to build up and cause contact and signal breakdown ( often exacerbated by heat) which leads to the problem seemingly occurring after a reset and/or when the bike is cold.
 I would agree with everything Graeme has said vis a vis fiddling with the TB set-up.
 Good luck with it. If you wrench on bikes at all, you'll not find the work too difficult. It needs set-up but this possible using the bikes OBD Diag interface. And some disasembly to get access is all...

  Just to add - there is a Dutch forum that is quite active. Im sure you can find alot of detail available in your mother tongue, if that appeals to you...!?
http://mt01.valenkamp.nl/index.php?PHPSESSID=i97oqf6ijommfghnhlph0p2nf6&action=forum

You too thanks for helping.
Good to read that you confirm the things segusted by Graeme.
I tried to register on the Dutch forum earlyer, but no respond so far.. Seems a little dead there unfortunatily. Also there's a German forum Donnermeister but English is easyer to read then German for me.