Cleaned & checked gas furnace. Inspected heat exchanger & flue venting. cleaned burners & flame sensor. Checked voltage & amp draw of motors. Test capacitor. Found run capacitor weak: 22%low. Replaced capacitor and tested amp draw. Checked filter. Checked combustion zone: good. Customer removed door to basement to balance pressure. Blower: 4.9A . Inducer: 1.4A . Gas pressure: 3.4 inches water column. Temperature rise: 57 . Supply: 126 . Return: 69 .