Goodman furnace comes on and works for a while. Then I can feel cool air blowing and I can hear the burners come on for a few seconds then they go off for a few seconds then they come back on for a few seconds and go off over and over. The blower continues and I can understand the cool air. Why will the burners not stay on long enough to heat the air? I can turn the heat down so the unit will settle for awhile, the turn it back on and it will work for an hour or longer then start messing up again.

Most likely something causing your pressure switch to kick in and out.