Gas flow is good given that the burner is still lit after the fridge stops cooling. The heat stack is all clear as well.Maybe sound crazy but check if you are getting gas to the fridge if it stops it like no fuel to burn also check out door and look if your burner tube is blocked with debris
It has been in the 90's and over 100 when this happened. Helping that heat out of the stack makes good sense. The stack is clean as well the area around the coils. Thanks.How hot is it outside? If it's above the mid 90s the chimney effect that carries waste heat away from the coils on the rear of the refrigerator can break down. Same if the area behind the refrigerator or the top vent is clogged. If it's just heat related adding a small fan to blow air upwards past the ooils can restore enough air circulation to let the fridge start cooing again.