Furnace keeps kicking off and on
I had a similar problem in which the furnace would start its pre-purge cycle, and then shut off.  The root cause was a broken solder joint on the controller circuit board, which I was able to see with strong reading glasses, and later repair by myself.
Try wiggling the low voltage electrical cables when your furnace acts up.  If you find an intermittent contact, it could be due to one or more broken solder joints.