A faulty or sticking idle air control valve can lead to hard starting and low or stalling idle if not openning.  If sticking open, a lean condition with popping or misfiring at speed or under load can occur.  This part is not available on its own from Yamaha or Arctic Cat, but comes as part of the throttle body assembly which costs over $1000 Cdn. 
 
We've sourced this part and are making it available on its own at a very reasonable price.