It could be reverse sneezing alot of Yorkies do this:
Reverse Sneezing (Pharyngeal Gag Reflex) - VeterinaryPartner.com - a VIN company!
Here's Momo doin it:
I just cover his nose, or rub his throat gently to have him swallow & he'll stop. If it was collapsed trachea, rubbing the throat will cause him/her to have the attack/honking sound more.