Make : YORK Deluxe DiamoD (2 stage)
Model : P1DUC20N09601B

(My unit is 5-7 year old we change are HVAC to new when we did edition to are home)

I have issue with my YORK. Some time fan continue work after heat stop (it take some time 1-1.5hr) and then it stop.
I call service who instal my HVAC.
Call twice and with tool and diagnostic no problem is fund.
Suggested is change Main board controller. (but none of them positive this is a main problem)
Only way to identify issue they have to be here (it is not possible to get them in 15-30min) when this happen
It also mention to thermostat may create problem or heat thermostat in my unit failing

If it fail:red light is flashing

Already Tried:
I turn Off thermostat and disconnect big cable from control board for 1-3min. Connect cable, turn on thermostat to auto/HEAT. (it work for some time hours) and this night still problem return
Unit blow cold air for time, and (time to time can't open all gas blower - only first one / other have delay) no consistency

Thank you