On Thursday, January 26, 2017 at 7:51:13 AM UTC-5, wrote:
There are dampers available for furnace air intake vents and are relatively inexpensive, but are controlled electrically and may require a technician to install. Also this may not entirely solve the problem, especially when the outside air temperature is below zero. But will lessen the occurrence of frost build up.

My high efficiency furnace uses a concentric vent pipe for exhaust/intake.
Issues started happening January 2018 when it got very cold.

Short heating cycles on 2nd stage heat that were not heating up the house fast enough.

My furnace is new and under warranty. The technician came today and found that the gas pressure was too high and the safety switch was shutting down the furnace due to excessive heat.

He adjusted the gas pressure valve and it seems to be working right now.