When your house goes into forecloser do you have to maintain insurance on the property?

ABSOLUTELY.
Your still bound by the terms of the loan, which include maintaining insurance.
If you don't, the loan Co will buy it and charge you. For many reasons, (especially since owners that need this to happen seem to have a much greater risk of experiencing a fire or loss), that insurance is much more expensive than what you'll get....and the loan co only insures the amount they need...the existing mortgage...and none of your personal belongings or liability (which are all covered under your normal homeowners).

And you understand that you will be responsible for any amount that the eventual sale of the property doesn't raise toward the total (that is all back payments, penalties, interest, and charges to foreclose, etc) owed? They just don't do it all for you for free.