sticky throttle mazda 6

[Andy70]

clutching at straws here really, I'm not sure if I'd get much response here, but my partner has a 2010 mazda 6 estate 2.2 deasil and I notice that sometimes that the throttle sticks wide open, is this a known issue does any one know? I'm assuming its a drive by wire setup so could be a throttle position sensor gone maybe? it doesn't do it all the time. hope someone can help. cheers