My furnace, Nordyne: model # mmhb-070abhr will not blow for more than a minute. It kicks in, blows warm air and shuts off. It keeps doing this over and over again. What can I do??

Sounds like the blower temperature control (fan/Limit) is switching on then off. This is a temperature control and is adjustable. Set the low temperature to 95 deg or higher. You really should replacde this control, and make sure there is no outside cold air getting into the air return. The colder air can cause the air through the furnace to shut down the fan control.