http://www.dsmtuners.com/threads/removing-coolant-line-from-throttle-body.359207/
Read through this. Should give you an answer. But you do need to block it some how or idle will be crap.

I would recommend using the bypass plate.

Yes you will still need to do the block off, otherwise the fiav will never close, giving you high idle.

Are you currently getting surge or high idle? What is your main reason for wanting to delete the coolant lines to the TB? After I fixed my thermostat and replaced my iac, my idle issues have been solved. No more surge or wierd idle, and i was planning on turning the fiav in or deleting it.

if the car is dying after running for a bit, look at the iac or coolant temp sensors first.