Performed furnace clean and tune; started by removing and cleaning the burners along with the flame sensor, I then vacuumed out the soot from inside of burner box, next I cycled the system on and checked gas pressures also noticed system having intermittent issues keeping the system on I did find that the flame sensor had been taped at the wire (possibly a past short), lastly performed a combustion test verifying no CO in the airstream. Due to age, condition, and cost to repair I highly recommend replacement of the furnace. Job complete UNPAID