At The End Of The Heating Cycle On My Furnace I Hear A Popping Bang?

is it coming from the duct work?? If so probably lack of return air... if you need to add a return, you might try putting a 6x12 grill on the return drop

Cracked heat exchangers will also do this. Might be a good idea to call in the pro's if you find out it is not coming from the ductwork, usually if it is the ductwork it will only do it right as the blower is turning on or off, and not on the cooldown cycle.